Systems and methods for signaling sequence parameter information in video coding

ABSTRACT

A device may be configured to signal sequence parameter information according to one or more of the techniques described herein. The sequence parameter set information may include in its second byte a syntax element specifying a chroma sampling relative to a luma sampling and a syntax element specifies a luma coding tree block size of each coding tree unit.

TECHNICAL FIELD

This disclosure relates to video coding and more particularly totechniques for signaling sequence parameter information for coded video.

BACKGROUND

Digital video capabilities can be incorporated into a wide range ofdevices, including digital televisions, laptop or desktop computers,tablet computers, digital recording devices, digital media players,video gaming devices, cellular telephones, including so-calledsmartphones, medical imaging devices, and the like. Digital video may becoded according to a video coding standard. Video coding standardsdefine the format of a compliant bitstream encapsulating coded videodata. A compliant bitstream is a data structure that may be received anddecoded by a video decoding device to generate reconstructed video data.Video coding standards may incorporate video compression techniques.Examples of video coding standards include ISO/IEC MPEG-4 Visual andITU-T H.264 (also known as ISO/IEC MPEG-4 AVC) and High-Efficiency VideoCoding (HEVC). HEVC is described in High Efficiency Video Coding (HEVC),Rec. ITU-T H.265, December 2016, which is incorporated by reference, andreferred to herein as ITU-T H.265. Extensions and improvements for ITU-TH.265 are currently being considered for the development of nextgeneration video coding standards. For example, the ITU-T Video CodingExperts Group (VCEG) and ISO/IEC (Moving Picture Experts Group (MPEG)(collectively referred to as the Joint Video Exploration Team (JVET))are working to standardized video coding technology with a compressioncapability that significantly exceeds that of the current HEVC standard.The Joint Exploration Model 7 (JEM 7), Algorithm Description of JointExploration Test Model 7 (JEM 7), ISO/IEC JTC1/SC29/WG11 Document:JVET-G1001, July 2017, Torino, IT, which is incorporated by referenceherein, describes the coding features that were under coordinated testmodel study by the JVET as potentially enhancing video coding technologybeyond the capabilities of ITU-T H.265. It should be noted that thecoding features of JEM 7 are implemented in JEM reference software. Asused herein, the term JEM may collectively refer to algorithms includedin JEM 7 and implementations of JEM reference software. Further, inresponse to a “Joint Call for Proposals on Video Compression withCapabilities beyond HEVC,” jointly issued by VCEG and MPEG, multipledescriptions of video coding tools were proposed by various groups atthe 10^(th) Meeting of ISO/IEC JTC1/SC29/WG11 16-20 Apr. 2018, SanDiego, Calif. From the multiple descriptions of video coding tools, aresulting initial draft text of a video coding specification isdescribed in “Versatile Video Coding (Draft 1),” 10^(th) Meeting ofISO/IEC JTC1/SC29/WG11 16-20 Apr. 2018, San Diego, Calif., documentJVET-J1001-v2, which is incorporated by reference herein, and referredto as JVET-J1001. The current development of a next generation videocoding standard by the VCEG and MPEG is referred to as the VersatileVideo Coding (VVC) project. “Versatile Video Coding (Draft 9),” 18thMeeting of ISO/IEC JTC1/SC29/WG11 15-24 Apr. 2020, Teleconference,document JVET-R2001-vA, which is incorporated by reference herein, andreferred to as JVET-R2001, represents the current iteration of the drafttext of a video coding specification corresponding to the VVC project.

Video compression techniques enable data requirements for storing andtransmitting video data to be reduced. Video compression techniques mayreduce data requirements by exploiting the inherent redundancies in avideo sequence. Video compression techniques may sub-divide a videosequence into successively smaller portions (i.e., groups of pictureswithin a video sequence, a picture within a group of pictures, regionswithin a picture, sub-regions within regions, etc.). Intra predictioncoding techniques (e.g., spatial prediction techniques within a picture)and inter prediction techniques (i.e., inter-picture techniques(temporal)) may be used to generate difference values between a unit ofvideo data to be coded and a reference unit of video data. Thedifference values may be referred to as residual data. Residual data maybe coded as quantized transform coefficients. Syntax elements may relateresidual data and a reference coding unit (e.g., intra-prediction modeindices, and motion information). Residual data and syntax elements maybe entropy coded. Entropy encoded residual data and syntax elements maybe included in data structures forming a compliant bitstream.

SUMMARY OF INVENTION

A method of decoding video data, the method comprising:

receiving a sequence parameter set including syntax elementscorresponding to a coded video sequence;

parsing a first byte of the sequence parameter set including a firstsyntax element and a second syntax element, wherein the first syntaxelement provides an identifier for the sequence parameter set, and thesecond syntax element specifies a video parameter set identifierreferred to by the sequence parameter set; and

parsing a second byte of the sequence parameter set including a thirdsyntax element, a fourth syntax element, a fifth syntax element and asixth syntax element, wherein the third syntax element specifies amaximum number of temporal sublayers that may be present in the codedvideo sequence referring to the sequence parameter set, the fourthsyntax element specifies a chroma sampling relative to a luma sampling,the fifth syntax element specifies a luma coding tree block size of eachcoding tree unit, and the sixth syntax element specifies whether levelinformation is present in the sequence parameter set.

A device comprising one or more processors configured to:

receive a sequence parameter set including syntax elements correspondingto a coded video sequence;

parse a first byte of the sequence parameter set including a firstsyntax element and a second syntax element, wherein the first syntaxelement provides an identifier for the sequence parameter set, and thesecond syntax element specifies a video parameter set identifierreferred to by the sequence parameter set; and

parse a second byte of the sequence parameter set including a thirdsyntax element, a fourth syntax element, a fifth syntax element and asixth syntax element, wherein the third syntax element specifies amaximum number of temporal sublayers that may be present in the codedvideo sequence referring to the sequence parameter set, the fourthsyntax element specifies a chroma sampling relative to a luma sampling,the fifth syntax element specifies a luma coding tree block size of eachcoding tree unit, and the sixth syntax element specifies whether levelinformation is present in the sequence parameter set.

A method of signaling parameters for video data, the method comprising:

signaling a first syntax element provides an identifier for a sequenceparameter set;

signaling a second syntax element specifies a video parameter setidentifier referred to by the sequence parameter set;

signaling a third syntax element specifying a maximum number of temporalsublayers that may be present in a coded video sequence referring to thesequence parameter set;

signaling a fourth syntax element specifying a chroma sampling to a lumasampling;

signaling a fifth syntax element specifying a luma coding tree blocksize of each coding tree unit;

signaling a sixth syntax element specifying whether level information ispresent in the sequence parameter set;

signaling a first byte of the sequence parameter set including the firstsyntax element and the second syntax element; and

signaling a second byte of the sequence parameter set including thethird syntax element, the fourth syntax element, the fifth syntaxelement and the sixth syntax element.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating an example of a system that maybe configured to encode and decode video data according to one or moretechniques of this disclosure.

FIG. 2 is a conceptual diagram illustrating coded video data andcorresponding data structures according to one or more techniques ofthis disclosure.

FIG. 3 is a conceptual diagram illustrating a data structureencapsulating coded video data and corresponding metadata according toone or more techniques of this disclosure.

FIG. 4 is a conceptual drawing illustrating an example of componentsthat may be included in an implementation of a system that may beconfigured to encode and decode video data according to one or moretechniques of this disclosure.

FIG. 5 is a block diagram illustrating an example of a video encoderthat may be configured to encode video data according to one or moretechniques of this disclosure.

FIG. 6 is a block diagram illustrating an example of a video decoderthat may be configured to decode video data according to one or moretechniques of this disclosure.

DETAILED DESCRIPTION

In general, this disclosure describes various techniques for codingvideo data. In particular, this disclosure describes techniques forsignaling parameter information for coded video data. It should be notedthat although techniques of this disclosure are described with respectto ITU-T H.264, ITU-T H.265, JEM, and JVET-R2001, the techniques of thisdisclosure are generally applicable to video coding. For example, thecoding techniques described herein may be incorporated into video codingsystems, (including video coding systems based on future video codingstandards) including video block structures, intra predictiontechniques, inter prediction techniques, transform techniques, filteringtechniques, and/or entropy coding techniques other than those includedin ITU-T H.265, JEM, and JVET-R2001. Thus, reference to ITU-T H.264,ITU-T H.265, JEM, and/or JVET-R2001 is for descriptive purposes andshould not be construed to limit the scope of the techniques describedherein. Further, it should be noted that incorporation by reference ofdocuments herein is for descriptive purposes and should not be construedto limit or create ambiguity with respect to terms used herein. Forexample, in the case where an incorporated reference provides adifferent definition of a term than another incorporated referenceand/or as the term is used herein, the term should be interpreted in amanner that broadly includes each respective definition and/or in amanner that includes each of the particular definitions in thealternative.

In one example, a method of signaling parameters for video datacomprises signaling a syntax element in a sequence parameter set syntaxstructure specifying a maximum number of temporal sublayers that may bepresent in each coded video sequence referring to the sequence parameterset, signaling a syntax element specifying a chroma sampling, andsignaling a syntax element specifying a luma coding tree block size,wherein the syntax element specifying a chroma sampling and the syntaxelement specifying a luma coding tree block size immediately follow thesyntax element specifying a maximum number of temporal sublayers.

In one example, a device comprises one or more processors configured tosignal a syntax element in a sequence parameter set syntax structurespecifying a maximum number of temporal sublayers that may be present ineach coded video sequence referring to the sequence parameter set,signal a syntax element specifying a chroma sampling, and signal asyntax element specifying a luma coding tree block size, wherein thesyntax element specifying a chroma sampling and the syntax elementspecifying a luma coding tree block size immediately follow the syntaxelement specifying a maximum number of temporal sublayers.

In one example, a non-transitory computer-readable storage mediumcomprises instructions stored thereon that, when executed, cause one ormore processors of a device to signal a syntax element in a sequenceparameter set syntax structure specifying a maximum number of temporalsublayers that may be present in each coded video sequence referring tothe sequence parameter set, signal a syntax element specifying a chromasampling, and signal a syntax element specifying a luma coding treeblock size, wherein the syntax element specifying a chroma sampling andthe syntax element specifying a luma coding tree block size immediatelyfollow the syntax element specifying a maximum number of temporalsublayers.

In one example, an apparatus comprises means for signaling a syntaxelement in a sequence parameter set syntax structure specifying amaximum number of temporal sublayers that may be present in each codedvideo sequence referring to the sequence parameter set, means forsignaling a syntax element specifying a chroma sampling, and means forsignaling a syntax element specifying a luma coding tree block size,wherein the syntax element specifying a chroma sampling and the syntaxelement specifying a luma coding tree block size immediately follow thesyntax element specifying a maximum number of temporal sublayers.

In one example, a method of decoding video data comprises parsing asyntax element in a sequence parameter set syntax structure specifying amaximum number of temporal sublayers that may be present in each codedvideo sequence referring to the sequence parameter set, parsing a syntaxelement specifying a chroma sampling, and parsing a syntax elementspecifying a luma coding tree block size, wherein the syntax elementspecifying a chroma sampling and the syntax element specifying a lumacoding tree block size immediately follow the syntax element specifyinga maximum number of temporal sublayers.

In one example, a device comprises one or more processors configured toparse a syntax element in a sequence parameter set syntax structurespecifying a maximum number of temporal sublayers that may be present ineach coded video sequence referring to the sequence parameter set, parsea syntax element specifying a chroma sampling, and parse a syntaxelement specifying a luma coding tree block size, wherein the syntaxelement specifying a chroma sampling and the syntax element specifying aluma coding tree block size immediately follow the syntax elementspecifying a maximum number of temporal sublayers.

In one example, a non-transitory computer-readable storage mediumcomprises instructions stored thereon that, when executed, cause one ormore processors of a device to parse a syntax element in a sequenceparameter set syntax structure specifying a maximum number of temporalsublayers that may be present in each coded video sequence referring tothe sequence parameter set, parse a syntax element specifying a chromasampling, and parse a syntax element specifying a luma coding tree blocksize, wherein the syntax element specifying a chroma sampling and thesyntax element specifying a luma coding tree block size immediatelyfollow the syntax element specifying a maximum number of temporalsublayers.

In one example, an apparatus comprises means for parsing a syntaxelement in a sequence parameter set syntax structure specifying amaximum number of temporal sublayers that may be present in each codedvideo sequence referring to the sequence parameter set, means forparsing a syntax element specifying a chroma sampling, and means forparsing a syntax element specifying a luma coding tree block size,wherein the syntax element specifying a chroma sampling and the syntaxelement specifying a luma coding tree block size immediately follow thesyntax element specifying a maximum number of temporal sublayers.

The details of one or more examples are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

Video content includes video sequences comprised of a series of frames(or pictures). A series of frames may also be referred to as a group ofpictures (GOP). Each video frame or picture may divided into one or moreregions. Regions may be defined according to a base unit (e.g., a videoblock) and sets of rules defining a region. For example, a rule defininga region may be that a region must be an integer number of video blocksarranged in a rectangle. Further, video blocks in a region may beordered according to a scan pattern (e.g., a raster scan). As usedherein, the term video block may generally refer to an area of a pictureor may more specifically refer to the largest array of sample valuesthat may be predictively coded, sub-divisions thereof, and/orcorresponding structures. Further, the term current video block mayrefer to an area of a picture being encoded or decoded. A video blockmay be defined as an array of sample values. It should be noted that insome cases pixel values may be described as including sample values forrespective components of video data, which may also be referred to ascolor components, (e.g., luma (Y) and chroma (Cb and Cr) components orred, green, and blue components). It should be noted that in some cases,the terms pixel value and sample value are used interchangeably.Further, in some cases, a pixel or sample may be referred to as a pel. Avideo sampling format, which may also be referred to as a chroma format,may define the number of chroma samples included in a video block withrespect to the number of luma samples included in a video block. Forexample, for the 4:2:0 sampling format, the sampling rate for the lumacomponent is twice that of the chroma components for both the horizontaland vertical directions.

A video encoder may perform predictive encoding on video blocks andsub-divisions thereof. Video blocks and sub-divisions thereof may bereferred to as nodes. ITU-T H.264 specifies a macroblock including 16×16luma samples. That is, in ITU-T H.264, a picture is segmented intomacroblocks. ITU-T H.265 specifies an analogous Coding Tree Unit (CTU)structure (which may be referred to as a largest coding unit (LCU)). InITU-T H.265, pictures are segmented into CTUs. In ITU-T H.265, for apicture, a CTU size may be set as including 16×16, 32×32, or 64×64 lumasamples. In ITU-T H.265, a CTU is composed of respective Coding TreeBlocks (CTB) for each component of video data (e.g., luma (Y) and chroma(Cb and Cr). It should be noted that video having one luma component andthe two corresponding chroma components may be described as having twochannels, i.e., a luma channel and a chroma channel. Further, in ITU-TH.265, a CTU may be partitioned according to a quadtree (QT)partitioning structure, which results in the CTBs of the CTU beingpartitioned into Coding Blocks (CB). That is, in ITU-T H.265, a CTU maybe partitioned into quadtree leaf nodes. According to ITU-T H.265, oneluma CB together with two corresponding chroma CBs and associated syntaxelements are referred to as a coding unit (CU). In ITU-T H.265, aminimum allowed size of a CB may be signaled. In ITU-T H.265, thesmallest minimum allowed size of a luma CB is 8×8 luma samples. In ITU-TH.265, the decision to code a picture area using intra prediction orinter prediction is made at the CU level.

In ITU-T H.265, a CU is associated with a prediction unit structurehaving its root at the CU. In ITU-T H.265, prediction unit structuresallow luma and chroma CBs to be split for purposes of generatingcorresponding reference samples. That is, in ITU-T H.265, luma andchroma CBs may be split into respective luma and chroma predictionblocks (PBs), where a PB includes a block of sample values for which thesame prediction is applied. In ITU-T H.265, a CB may be partitioned into1, 2, or 4 PBs. ITU-T H.265 supports PB sizes from 64×64 samples down to4×4 samples. In ITU-T H.265, square PBs are supported for intraprediction, where a CB may form the PB or the CB may be split into foursquare PBs. In ITU-T H.265, in addition to the square PBs, rectangularPBs are supported for inter prediction, where a CB may be halvedvertically or horizontally to form PBs. Further, it should be noted thatin ITU-T H.265, for inter prediction, four asymmetric PB partitions aresupported, where the CB is partitioned into two PBs at one quarter ofthe height (at the top or the bottom) or width (at the left or theright) of the CB. Intra prediction data (e.g., intra prediction modesyntax elements) or inter prediction data (e.g., motion data syntaxelements) corresponding to a PB is used to produce reference and/orpredicted sample values for the PB.

JEM specifies a CTU having a maximum size of 256×256 luma samples. JEMspecifies a quadtree plus binary tree (QTBT) block structure. In JEM,the QTBT structure enables quadtree leaf nodes to be further partitionedby a binary tree (BT) structure. That is, in JEM, the binary treestructure enables quadtree leaf nodes to be recursively dividedvertically or horizontally. In JVET-R2001, CTUs are partitionedaccording a quadtree plus multi-type tree (QTMT or QT+MTT) structure.The QTMT in JVET-R2001 is similar to the QTBT in JEM. However, inJVET-R2001, in addition to indicating binary splits, the multi-type treemay indicate so-called ternary (or triple tree (TT)) splits. A ternarysplit divides a block vertically or horizontally into three blocks. Inthe case of a vertical TT split, a block is divided at one quarter ofits width from the left edge and at one quarter its width from the rightedge and in the case of a horizontal TT split a block is at one quarterof its height from the top edge and at one quarter of its height fromthe bottom edge.

As described above, each video frame or picture may be divided into oneor more regions. For example, according to ITU-T H.265, each video frameor picture may be partitioned to include one or more slices and furtherpartitioned to include one or more tiles, where each slice includes asequence of CTUs (e.g., in raster scan order) and where a tile is asequence of CTUs corresponding to a rectangular area of a picture. Itshould be noted that a slice, in ITU-T H.265, is a sequence of one ormore slice segments starting with an independent slice segment andcontaining all subsequent dependent slice segments (if any) that precedethe next independent slice segment (if any). A slice segment, like aslice, is a sequence of CTUs. Thus, in some cases, the terms slice andslice segment may be used interchangeably to indicate a sequence of CTUsarranged in a raster scan order. Further, it should be noted that inITU-T H.265, a tile may consist of CTUs contained in more than one sliceand a slice may consist of CTUs contained in more than one tile.However, ITU-T H.265 provides that one or both of the followingconditions shall be fulfilled: (1) All CTUs in a slice belong to thesame tile; and (2) All CTUs in a tile belong to the same slice.

With respect to JVET-R2001, slices are required to consist of an integernumber of complete tiles or an integer number of consecutive completeCTU rows within a tile, instead of only being required to consist of aninteger number of CTUs. It should be noted that in JVET-R2001, the slicedesign does not include slice segments (i.e., no independent/dependentslice segments). Thus, in JVET-R2001, a picture may include a singletile, where the single tile is contained within a single slice or apicture may include multiple tiles where the multiple tiles (or CTU rowsthereof) may be contained within one or more slices. In JVET-R2001, thepartitioning of a picture into tiles is specified by specifyingrespective heights for tile rows and respective widths for tile columns.Thus, in JVET-R2001 a tile is a rectangular region of CTUs within aparticular tile row and a particular tile column position. Further, itshould be noted that JVET-R2001 provides where a picture may bepartitioned into subpictures, where a subpicture is a rectangular regionof a CTUs within a picture. The top-left CTU of a subpicture may belocated at any CTU position within a picture with subpictures beingconstrained to include one or more slices Thus, unlike a tile, asubpicture is not necessarily limited to a particular row and columnposition. It should be noted that subpictures may be useful forencapsulating regions of interest within a picture and a sub-bitstreamextraction process may be used to only decode and display a particularregion of interest. That is, as described in further detail below, abitstream of coded video data includes a sequence of network abstractionlayer (NAL) units, where a NAL unit encapsulates coded video data,(i.e., video data corresponding to a slice of picture) or a NAL unitencapsulates metadata used for decoding video data (e.g., a parameterset) and a sub-bitstream extraction process forms a new bitstream byremoving one or more NAL units from a bitstream.

FIG. 2 is a conceptual diagram illustrating an example of a picturewithin a group of pictures partitioned according to tiles, slices, andsubpictures. It should be noted that the techniques described herein maybe applicable to tiles, slices, subpictures, sub-divisions thereofand/or equivalent structures thereto. That is, the techniques describedherein may be generally applicable regardless of how a picture ispartitioned into regions. For example, in some cases, the techniquesdescribed herein may be applicable in cases where a tile may bepartitioned into so-called bricks, where a brick is a rectangular regionof CTU rows within a particular tile. Further, for example, in somecases, the techniques described herein may be applicable in cases whereone or more tiles may be included in so-called tile groups, where a tilegroup includes an integer number of adjacent tiles. In the exampleillustrated in FIG. 2, Pic₃ is illustrated as including 16 tiles (i.e.,Tile₀ to Tile₁₅) and three slices (i.e., Slice₀ to Slice₂). In theexample illustrated in FIG. 2, Slice® includes four tiles (i.e., Tile₀to Tile₃), Slice₁ includes eight tiles (i.e., Tile₄ to Tile₁₁), andSlice₂ includes four tiles (i.e., Tile₁₂ to Tile₁₅). Further, asillustrated in the example of FIG. 2, Pic₃ is illustrated as includingtwo subpictures (i.e., Subpicture₀ and Subpicture₁), where Subpicture₀includes Slice₀ and Slice₁ and where Subpicture₁ includes Slice₂. Asdescribed above, subpictures may be useful for encapsulating regions ofinterest within a picture and a sub-bitstream extraction process may beused in order to selectively decode (and display) a region interest. Forexample, referring to FIG. 2, Subpicture₀ may corresponding to an actionportion of a sporting event presentation (e.g., a view of the field) andSubpicture₁ may corresponding to a scrolling banner displayed during thesporting event presentation. By using organizing a picture intosubpictures in this manner, a viewer may be able to disable the displayof the scrolling banner. That is, through a sub-bitstream extractionprocess Slice₂ NAL unit may be removed from a bitstream (and thus notdecoded and/or displayed) and Slice₀ NAL unit and Slice₁ NAL unit may bedecoded and displayed. The encapsulation of slices of a picture intorespective NAL unit data structures and sub-bitstream extraction aredescribed in further detail below.

For intra prediction coding, an intra prediction mode may specify thelocation of reference samples within a picture. In ITU-T H.265, definedpossible intra prediction modes include a planar (i.e., surface fitting)prediction mode, a DC (i.e., flat overall averaging) prediction mode,and 33 angular prediction modes (predMode: 2-34). In JEM, definedpossible intra-prediction modes include a planar prediction mode, a DCprediction mode, and 65 angular prediction modes. It should be notedthat planar and DC prediction modes may be referred to asnon-directional prediction modes and that angular prediction modes maybe referred to as directional prediction modes. It should be noted thatthe techniques described herein may be generally applicable regardlessof the number of defined possible prediction modes.

For inter prediction coding, a reference picture is determined and amotion vector (MV) identifies samples in the reference picture that areused to generate a prediction for a current video block. For example, acurrent video block may be predicted using reference sample valueslocated in one or more previously coded picture(s) and a motion vectoris used to indicate the location of the reference block relative to thecurrent video block. A motion vector may describe, for example, ahorizontal displacement component of the motion vector (i.e., MV_(x)), avertical displacement component of the motion vector (i.e., MV_(y)), anda resolution for the motion vector (e.g., one-quarter pixel precision,one-half pixel precision, one-pixel precision, two-pixel precision,four-pixel precision). Previously decoded pictures, which may includepictures output before or after a current picture, may be organized intoone or more to reference pictures lists and identified using a referencepicture index value. Further, in inter prediction coding, uni-predictionrefers to generating a prediction using sample values from a singlereference picture and bi-prediction refers to generating a predictionusing respective sample values from two reference pictures. That is, inuni-prediction, a single reference picture and corresponding motionvector are used to generate a prediction for a current video block andin bi-prediction, a first reference picture and corresponding firstmotion vector and a second reference picture and corresponding secondmotion vector are used to generate a prediction for a current videoblock. In bi-prediction, respective sample values are combined (e.g.,added, rounded, and clipped, or averaged according to weights) togenerate a prediction. Pictures and regions thereof may be classifiedbased on which types of prediction modes may be utilized for encodingvideo blocks thereof. That is, for regions having a B type (e.g., a Bslice), bi-prediction, uni-prediction, and intra prediction modes may beutilized, for regions having a P type (e.g., a P slice), uni-prediction,and intra prediction modes may be utilized, and for regions having an Itype (e.g., an I slice), only intra prediction modes may be utilized. Asdescribed above, reference pictures are identified through referenceindices. For example, for a P slice, there may be a single referencepicture list, RefPicList0 and for a B slice, there may be a secondindependent reference picture list, RefPicList1, in addition toRefPicList0. It should be noted that for uni-prediction in a B slice,one of RefPicList0 or RefPicList1 may be used to generate a prediction.Further, it should be noted that during the decoding process, at theonset of decoding a picture, reference picture list(s) are generatedfrom previously decoded pictures stored in a decoded picture buffer(DPB).

Further, a coding standard may support various modes of motion vectorprediction. Motion vector prediction enables the value of a motionvector for a current video block to be derived based on another motionvector. For example, a set of candidate blocks having associated motioninformation may be derived from spatial neighboring blocks and temporalneighboring blocks to the current video block. Further, generated (ordefault) motion information may be used for motion vector prediction.Examples of motion vector prediction include advanced motion vectorprediction (AMVP), temporal motion vector prediction (TMVP), so-called“merge” mode, and “skip” and “direct” motion inference. Further, otherexamples of motion vector prediction include advanced temporal motionvector prediction (ATMVP) and Spatial-temporal motion vector prediction(STMVP). For motion vector prediction, both a video encoder and videodecoder perform the same process to derive a set of candidates. Thus,for a current video block, the same set of candidates is generatedduring encoding and decoding.

As described above, for inter prediction coding, reference samples in apreviously coded picture are used for coding video blocks in a currentpicture. Previously coded pictures which are available for use asreference when coding a current picture are referred as referencepictures. It should be noted that the decoding order does not necessarycorrespond with the picture output order, i.e., the temporal order ofpictures in a video sequence. In ITU-T H.265, when a picture is decodedit is stored to a decoded picture buffer (DPB) (which may be referred toas frame buffer, a reference buffer, a reference picture buffer, or thelike). In ITU-T H.265, pictures stored to the DPB are removed from theDPB when they been output and are no longer needed for coding subsequentpictures. In ITU-T H.265, a determination of whether pictures should beremoved from the DPB is invoked once per picture, after decoding a sliceheader, i.e., at the onset of decoding a picture. For example, referringto FIG. 2, Pic₂ is illustrated as referencing Pic₁. Similarly, Pic₃ isillustrated as referencing Pic₀. With respect to FIG. 2, assuming thepicture number corresponds to the decoding order, the DPB would bepopulated as follows: after decoding Pic₀, the DPB would include {Pic₀};at the onset of decoding Pic₁, the DPB would include {Pic₀}; afterdecoding Pic₁, the DPB would include {Pic₀, Pic₁}; at the onset ofdecoding Pic₂, the DPB would include {Pic₀, Pic₁}. Pic₂ would then bedecoded with reference to Pic₁ and after decoding Pic₂, the DPB wouldinclude {Pic₀, Pic₁, Pic₂}. At the onset of decoding Pic₃, pictures Pic₀and Pic₁ would be marked for removal from the DPB, as they are notneeded for decoding Pic₃ (or any subsequent pictures, not shown) andassuming Pic₁ and Pic₂ have been output, the DPB would be updated toinclude {Pic₀}. Pic₃ would then be decoded by referencing Pic₀. Theprocess of marking pictures for removal from a DPB may be referred to asreference picture set (RPS) management.

As described above, intra prediction data or inter prediction data isused to produce reference sample values for a block of sample values.The difference between sample values included in a current PB, oranother type of picture area structure, and associated reference samples(e.g., those generated using a prediction) may be referred to asresidual data. Residual data may include respective arrays of differencevalues corresponding to each component of video data. Residual data maybe in the pixel domain. A transform, such as, a discrete cosinetransform (DCT), a discrete sine transform (DST), an integer transform,a wavelet transform, or a conceptually similar transform, may be appliedto an array of difference values to generate transform coefficients. Itshould be noted that in ITU-T H.265 and JVET-R2001, a CU is associatedwith a transform tree structure having its root at the CU level. Thetransform tree is partitioned into one or more transform units (TUs).That is, an array of difference values may be partitioned for purposesof generating transform coefficients (e.g., four 8×8 transforms may beapplied to a 16×16 array of residual values). For each component ofvideo data, such sub-divisions of difference values may be referred toas Transform Blocks (TBs). It should be noted that in some cases, a coretransform and subsequent secondary transforms may be applied (in thevideo encoder) to generate transform coefficients. For a video decoder,the order of transforms is reversed.

A quantization process may be performed on transform coefficients orresidual sample values directly (e.g., in the case, of palette codingquantization). Quantization approximates transform coefficients byamplitudes restricted to a set of specified values. Quantizationessentially scales transform coefficients in order to vary the amount ofdata required to represent a group of transform coefficients.Quantization may include division of transform coefficients (or valuesresulting from the addition of an offset value to transformcoefficients) by a quantization scaling factor and any associatedrounding functions (e.g., rounding to the nearest integer). Quantizedtransform coefficients may be referred to as coefficient level values.Inverse quantization (or “dequantization”) may include multiplication ofcoefficient level values by the quantization scaling factor, and anyreciprocal rounding or offset addition operations. It should be notedthat as used herein the term quantization process in some instances mayrefer to division by a scaling factor to generate level values andmultiplication by a scaling factor to recover transform coefficients insome instances. That is, a quantization process may refer toquantization in some cases and inverse quantization in some cases.Further, it should be noted that although in some of the examples belowquantization processes are described with respect to arithmeticoperations associated with decimal notation, such descriptions are forillustrative purposes and should not be construed as limiting. Forexample, the techniques described herein may be implemented in a deviceusing binary operations and the like. For example, multiplication anddivision operations described herein may be implemented using bitshifting operations and the like.

Quantized transform coefficients and syntax elements (e.g., syntaxelements indicating a coding structure for a video block) may be entropycoded according to an entropy coding technique. An entropy codingprocess includes coding values of syntax elements using lossless datacompression algorithms. Examples of entropy coding techniques includecontent adaptive variable length coding (CAVLC), context adaptive binaryarithmetic coding (CABAC), probability interval partitioning entropycoding (PIPE), and the like. Entropy encoded quantized transformcoefficients and corresponding entropy encoded syntax elements may forma compliant bitstream that can be used to reproduce video data at avideo decoder. An entropy coding process, for example, CABAC, mayinclude performing a binarization on syntax elements. Binarizationrefers to the process of converting a value of a syntax element into aseries of one or more bits. These bits may be referred to as “bins.”Binarization may include one or a combination of the following codingtechniques: fixed length coding, unary coding, truncated unary coding,truncated Rice coding, Golomb coding, k-th order exponential Golombcoding, and Golomb-Rice coding. For example, binarization may includerepresenting the integer value of 5 for a syntax element as 00000101using an 8-bit fixed length binarization technique or representing theinteger value of 5 as 11110 using a unary coding binarization technique.As used herein each of the terms fixed length coding, unary coding,truncated unary coding, truncated Rice coding, Golomb coding, k-th orderexponential Golomb coding, and Golomb-Rice coding may refer to generalimplementations of these techniques and/or more specific implementationsof these coding techniques. For example, a Golomb-Rice codingimplementation may be specifically defined according to a video codingstandard. In the example of CABAC, for a particular bin, a contextprovides a most probable state (MPS) value for the bin (i.e., an MPS fora bin is one of 0 or 1) and a probability value of the bin being the MPSor the least probably state (LPS). For example, a context may indicate,that the MPS of a bin is 0 and the probability of the bin being 1 is0.3. It should be noted that a context may be determined based on valuesof previously coded bins including bins in the current syntax elementand previously coded syntax elements. For example, values of syntaxelements associated with neighboring video blocks may be used todetermine a context for a current bin.

With respect to the equations used herein, the following arithmeticoperators may be used:

-   + Addition-   − Subtraction-   * Multiplication, including matrix multiplication-   x^(y) Exponentiation. Specifies x to the power of y. In other    contexts, such notation is used for superscripting not intended for    interpretation as exponentiation.-   / Integer division with truncation of the result toward zero. For    example, 7/4 and −7/−4 are truncated to 1 and −7/4 and 7/−4 are    truncated to −1.-   ÷ Used to denote division in mathematical equations where no    truncation or rounding is intended.

$\frac{x}{y}$Used to denote division in mathematical equations where no truncation orrounding is intended.

Further, the following mathematical functions may be used:

Log 2(x) the base-2 logarithm of x;

${{Min}\left( {x,y} \right)} = \left\{ {\begin{matrix}{x\ ;\ {{x <} = y}} \\{y\ ;\ {x > y}}\end{matrix};{{{Max}\left( {x,y} \right)} = \left\{ \begin{matrix}{x;{{x >} = y}} \\{y\ ;{x < y}}\end{matrix} \right.}} \right.$

Ceil(x) the smallest integer greater than or equal to x.

With respect to the example syntax used herein, the followingdefinitions of logical operators may be applied:

x && y Boolean logical “and” of x and y

x∥y Boolean logical “or” of x and y

! Boolean logical “not”

x?y: z If x is TRUE or not equal to 0, evaluates to the value of y;otherwise, evaluates to the value of z.

Further, the following relational operators may be applied:

> Greater than

>= Greater than or equal to

< Less than

<= Less than or equal to

= Equal to

!= Not equal to

Further, it should be noted that in the syntax descriptors used herein,the following descriptors may be applied:

-   -   b(8): byte having any pattern of bit string (8 bits). The        parsing process for this descriptor is specified by the return        value of the function read_bits (8).    -   f(n): fixed-pattern bit string using n bits written (from left        to right) with the left bit first. The parsing process for this        descriptor is specified by the return value of the function        read_bits (n).    -   se(v): signed integer 0-th order Exp-Golomb-coded syntax element        with the left bit first.    -   tb(v): truncated binary using up to maxVal bits with maxVal        defined in the semantics of the symtax element.    -   tu(v): truncated unary using up to maxVal bits with maxVal        defined in the semantics of the symtax element.    -   u(n): unsigned integer using n bits. When n is “v” in the syntax        table, the number of bits varies in a manner dependent on the        value of other syntax elements. The parsing process for this        descriptor is specified by the return value of the function        read_bits (n) interpreted as a binary representation of an        unsigned integer with most significant bit written first.    -   ue(v): unsigned integer 0-th order Exp-Golomb-coded syntax        element with the left bit first.

As described above, video content includes video sequences comprised ofa series of pictures and each picture may be divided into one or moreregions. In JVET-R2001, a coded representation of a picture comprisesVCL NAL units of a particular layer within an AU and contains all CTUsof the picture. For example, referring again to FIG. 2, the codedrepresentation of Pica is encapsulated in three coded slice NAL units(i.e., Slice₀ NAL unit, Slice₁ NAL unit, and Slice₂ NAL unit). It shouldbe noted that the term video coding layer (VCL) NAL unit is used as acollective term for coded slice NAL units, i.e., VCL NAL is a collectiveterm which includes all types of slice NAL units. As described above,and in further detail below, a NAL unit may encapsulate metadata usedfor decoding video data. A NAL unit encapsulating metadata used fordecoding a video sequence is generally referred to as a non-VCL NALunit. Thus, in JVET-R2001, a NAL unit may be a VCL NAL unit or a non-VCLNAL unit. It should be noted that a VCL NAL unit includes slice headerdata, which provides information used for decoding the particular slice.Thus, in JVET-R2001, information used for decoding video data, which maybe referred to as metadata in some cases, is not limited to beingincluded in non-VCL NAL units. JVET-R2001 provides where a picture unit(PU) is a set of NAL units that are associated with each other accordingto a specified classification rule, are consecutive in decoding order,and contain exactly one coded picture and where an access unit (AU) is aset of PUs that belong to different layers and contain coded picturesassociated with the same time for output from the DPB. JVET-R2001further provides where a layer is a set of VCL NAL units that all have aparticular value of a layer identifier and the associated non-VCL NALunits. Further, in JVET-R2001, a PU consists of zero or one PH NALunits, one coded picture, which comprises of one or more VCL NAL units,and zero or more other non-VCL NAL units. Further, in JVET-R2001, acoded video sequence (CVS) is a sequence of AUs that consists, indecoding order, of a CVSS AU, followed by zero or more AUs that are notCVSS AUs, including all subsequent AUs up to but not including anysubsequent AU that is a CVSS AU, where a coded video sequence start(CVSS) AU is an AU in which there is a PU for each layer in the CVS andthe coded picture in each present picture unit is a coded layer videosequence start (CLVSS) picture. In JVET-R2001, a coded layer videosequence (CLVS) is a sequence of PUs within the same layer thatconsists, in decoding order, of a CLVSS PU, followed by zero or more PUsthat are not CLVSS PUs, including all subsequent PUs up to but notincluding any subsequent PU that is a CLVSS PU. This is, in JVET-R2001,a bitstream may be described as including a sequence of AUs forming oneor more CVSs.

Multi-layer video coding enables a video presentation to bedecoded/displayed as a presentation corresponding to a base layer ofvideo data and decoded/displayed one or more additional presentationscorresponding to enhancement layers of video data. For example, a baselayer may enable a video presentation having a basic level of quality(e.g., a High Definition rendering and/or a 30 Hz frame rate) to bepresented and an enhancement layer may enable a video presentationhaving an enhanced level of quality (e.g., an Ultra High Definitionrendering and/or a 60 Hz frame rate) to be presented. An enhancementlayer may be coded by referencing a base layer. That is, for example, apicture in an enhancement layer may be coded (e.g., using inter-layerprediction techniques) by referencing one or more pictures (includingscaled versions thereof) in a base layer. It should be noted that layersmay also be coded independent of each other. In this case, there may notbe inter-layer prediction between two layers. Each NAL unit may includean identifier indicating a layer of video data the NAL unit isassociated with. As described above, a sub-bitstream extraction processmay be used to only decode and display a particular region of interestof a picture. Further, a sub-bitstream extraction process may be used toonly decode and display a particular layer of video. Sub-bitstreamextraction may refer to a process where a device receiving a compliantor conforming bitstream forms a new compliant or conforming bitstream bydiscarding and/or modifying data in the received bitstream. For example,sub-bitstream extraction may be used to form a new compliant orconforming bitstream corresponding to a particular representation ofvideo (e.g., a high quality representation).

In JVET-R2001, each of a video sequence, a GOP, a picture, a slice, andCTU may be associated with metadata that describes video codingproperties and some types of metadata an encapsulated in non-VCL NALunits. JVET-R2001 defines parameters sets that may be used to describevideo data and/or video coding properties. In particular, JVET-R2001includes the following four types of parameter sets: video parameter set(VPS), sequence parameter set (SPS), picture parameter set (PPS), andadaption parameter set (APS), where a SPS applies to apply to zero ormore entire CVSs, a PPS applies to zero or more entire coded pictures, aAPS applies to zero or more slices, and a VPS may be optionallyreferenced by a SPS. A PPS applies to an individual coded picture thatrefers to it. In JVET-R2001, parameter sets may be encapsulated as anon-VCL NAL unit and/or may be signaled as a message. JVET-R2001 alsoincludes a picture header (PH) which is encapsulated as a non-VCL NALunit. In JVET-R2001, a picture header applies to all slices of a codedpicture. JVET-R2001 further enables decoding capability information(DCI) and supplemental enhancement information (SEI) messages to besignaled. In JVET-R2001, DCI and SEI messages assist in processesrelated to decoding, display or other purposes, however, DCI and SEImessages may not be required for constructing the luma or chroma samplesaccording to a decoding process. In JVET-R2001, DCI and SEI messages maybe signaled in a bitstream using non-VCL NAL units. Further, DCI and SEImessages may be conveyed by some mechanism other than by being presentin the bitstream (i.e., signaled out-of-band).

FIG. 3 illustrates an example of a bitstream including multiple CVSs,where a CVS includes AUs, and AUs include picture units. The exampleillustrated in FIG. 3 corresponds to an example of encapsulating theslice NAL units illustrated in the example of FIG. 2 in a bitstream. Inthe example illustrated in FIG. 3, the corresponding picture unit forPic₃ includes the three VCL NAL coded slice NAL units, i.e., Slice₀ NALunit, Slice₁ NAL unit, and Slice₂ NAL unit and two non-VCL NAL units,i.e., a PPS NAL Unit and a PH NAL unit. It should be noted that in FIG.3, HEADER is a NAL unit header (i.e., not to be confused with a sliceheader). Further, it should be noted that in FIG. 3, other non-VCL NALunits, which are not illustrated may be included in the CVSs, e.g., SPSNAL units, VPS NAL units, SEI message NAL units, etc. Further, it shouldbe noted that in other examples, a PPS NAL Unit used for decoding Pic₃may be included elsewhere in the bitstream, e.g., in the picture unitcorresponding to Pic₀ or may be provided by an external mechanism. Asdescribed in further detail below, in JVET-R2001, a PH syntax structuremay be present in the slice header of a VCL NAL unit or in a PH NAL unitof the current PU.

JVET-R2001 defines NAL unit header semantics that specify the type ofRaw Byte Sequence Payload (RBSP) data structure included in the NALunit. Table 1 illustrates the syntax of the NAL unit header provided inJVET-R2001.

TABLE 1 nal_unit_header( ) { Descriptor  forbidden_zero_bit f(1) nuh_reserved_zero_bit u(1)  nuh_layer_id u(6)  nal_unit_type u(5) nuh_temporal_id_plus1 u(3) }

JVET-R2001 provides the following definitions for the respective syntaxelements illustrated in Table 1.

forbidden_zero_bit shall be equal to 0.

nuh_reserved_zero_bit shall be equal to ‘0’. The value 1 ofnuh_reserved_zero_bit may be specified in the future by ITU-T|ISO/IEC.Decoders shall ignore (i.e. remove from the bitstream and discard) NALunits with nuh_reserved_zero_bit equal to ‘1’.

nuh_layer_id specifies the identifier of the layer to which a VCL NALunit belongs or the identifier of a layer to which a non-VCL NAL unitapplies. The value of nuh_layer_id shall be in the range of 0 to 55,inclusive. Other values for nuh_layer_id are reserved for future use byITU-T|ISO/IEC.

The value of nuh_layer_id shall be the same for all VCL NAL units of acoded picture. The value of nuh_layer_id of a coded picture or a PU isthe value of the nuh_layer_id of the VCL NAL units of the coded pictureor the PU.

When nal_unit_type is equal to PH_NUT, EOS_NUT, or FD_NUT, nuh_layer_idshall be equal to the nuh_layer_id of associated VCL NAL unit.

-   -   NOTE—The value of nuh_layer_id of DCI, VPS, AUD, and EOB NAL        units is not constrained.

nuh_temporal_id_plus1 minus 1 specifies a temporal identifier for theNAL unit.

The value of nuh_temporal_id_plus1 shall not be equal to 0.

The variable TemporalId is derived as follows:TemporalId=nuh_temporal_id_plus1−1

When nal_unit_type is in the range of IDR_W_RADL to RSV_IRAP_12,inclusive, TemporalId shall be equal to 0. When nal_unit_type is equalto STSA_NUT andvps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 1,TemporalId shall not be equal to 0.

The value of TemporalId shall be the same for all VCL NAL units of anAU. The value of TemporalId of a coded picture, a PU, or an AU is thevalue of the TemporalId of the VCL NAL units of the coded picture, PU,or AU. The value of TemporalId of a sublayer representation is thegreatest value of TemporalId of all VCL NAL units in the sublayerrepresentation.

The value of TemporalId for non-VCL NAL units is constrained as follows:

-   -   If nal_unit_type is equal to DCI_NUT, VPS_NUT, or SPS_NUT,        TemporalId shall be equal to 0 and the TemporalId of the AU        containing the NAL unit shall be equal to 0.    -   Otherwise, if nal_unit_type is equal to PH_NUT, TemporalId shall        be equal to the TemporalId of the PU containing the NAL unit.    -   Otherwise, if nal_unit_type is equal to EOS_NUT or EOB_NUT,        TemporalId shall be equal to 0.    -   Otherwise, if nal_unit_type is equal to AUD_NUT, FD_NUT,        PREFIX_SEI_NUT, or SUFFIX_SEI_NUT, TemporalId shall be equal to        the TemporalId of the AU containing the NAL unit.    -   Otherwise, when nal_unit_type is equal to PPS_NUT,        PREFIX_APS_NUT, or SUFFIX_APS_NUT, TemporalId shall be greater        than or equal to the TemporalId of the PU containing the NAL        unit.

NOTE—When the NAL unit is a non-VCL NAL unit, the value of TemporalId isequal to the minimum value of the TemporalId values of all AUs to whichthe non-VCL NAL unit applies. When nal_unit_type is equal to PPS_NUT,PREFIX_APS_NUT, or SUFFIX_APS_NUT, TemporalId may be greater than orequal to the TemporalId of the containing AU, as all PPSs and APSs maybe included in the beginning of the bitstream (e.g., when they aretransported out-of-band, and the receiver places them at the beginningof the bitstream), wherein the first coded picture has TemporalId equalto 0.

nal_unit_type specifies the NAL unit type, i.e., the type of RBSP datastructure contained in the NAL unit as specified in Table 2.

The value of nal_unit_type shall be the same for all pictures of a CVSSAU.

NAL units that have nal_unit_type in the range of UNSPEC28 . . .UNSPEC31, inclusive, for which semantics are not specified, shall notaffect the decoding process specified in this Specification.

NOTE—NAL unit types in the range of UNSPEC28 . . . UNSPEC31 may be usedas determined by the application. No decoding process for these valuesof nal_unit_type is specified in this Specification. Since differentapplications might use these NAL unit types for different purposes,particular care must be exercised in the design of encoders thatgenerate NAL units with these nal_unit_type values, and in the design ofdecoders that interpret the content of NAL units with thesenal_unit_type values. This Specification does not define any managementfor these values. These nal_unit_type values might only be suitable foruse in contexts in which “collisions” of usage (i.e., differentdefinitions of the meaning of the NAL unit content for the samenal_unit_type value) are unimportant, or not possible, or aremanaged—e.g., defined or managed in the controlling application ortransport specification, or by controlling the environment in whichbitstreams are distributed.

For purposes other than determining the amount of data in the decodingunits of the bitstream, decoders shall ignore (remove from the bitstreamand discard) the contents of all NAL units that use reserved values ofnal_unit_type.

NOTE—This requirement allows future definition of compatible extensionsto this Specification.

TABLE 2 nal_ Content of NAL NAL unit_ Name of unit and RBSP unit typenal_unit_type syntax structure type class  0 TRAIL_NUT Coded slice of atrailing VCL picture or subpicture* slice_layer_rbsp( )  1 STSA_NUTCoded slice of an STSA VCL picture or subpicture* slice_layer_rbsp( )  2RADL_NUT Coded slice of a RADL VCL picture or subpicture*slice_layer_rbsp( )  3 RASL_NUT Coded slice of a RASL VCL picture orsubpicture* slice_layer_rbsp( )  4 . . . RSV_VCL_4 . . . Reservednon-IRAP VCL NAL VCL  6 RSV_VCL_6 unit types  7 IDR_W_RADL Coded sliceof an IDR picture VCL or subpicture*  8 IDR_N_LP slice_layer_rbsp( )  9CRA_NUT Coded slice of a CRA VCL picture or subpicture*silce_layer_rbsp( ) 10 GDR_NUT Coded slice of a GDR VCL picture orsubpicture* slice_layer_rbsp( ) 11 RSV_IRAP_11 Reserved IRAP VCL NAL VCL12 RSV_IRAP_12 unit types 13 DCI_NUT Decoding capability non-VCLinformation decoding_capability_ information_rbsp( ) 14 VPS_NUT Videoparameter set non-VCL video_parameter_set_rbsp( ) 15 SPS_NUT Sequenceparameter set non-VCL seq_parameter_set_rbsp( ) 16 PPS_NUT Pictureparameter set non-VCL pic_parameter_set_rbsp( ) 17 PREFIX_APS_NUTAdaptation parameter set non-VCL 18 SUFFIX_APS_NUT adaptation_parameter_set_rbsp( ) 19 PH_NUT Picture header non-VCL picture_header_rbsp( ) 20AUD_NUT AU delimiter non-VCL access_unit_delimiter_rbsp( ) 21 EOS_NUTEnd of sequence non-VCL end_of_seq_rbsp( ) 22 EOB_NUT End of bitstreamnon-VCL end_of_bitstream_rbsp( ) 23 PREFIX_SEI_NUT Supplementalenhancement non-VCL 24 SUFFIX_SEI_NUT information sei_rbsp( ) 25 FD_NUTFiller data non-VCL filler_data_rbsp( ) 26 RSV_NVCL_26 Reserved non-VCLNAL non-VCL 27 RSV_NVCL_27 unit types 28 . . . UNSPEC_28 . . .Unspecified non-VCL NAL non-VCL 31 UNSPEC_31 unit types *indicates aproperty of a picture when pps_mixed_nalu_types_in_pic_flag is equal to0 and a property of the subpicture when pps_mixed_nalu_types_in_pic_flagis equal to 1.

NOTE—A clean random access (CRA) picture may have associated RASL orRADL pictures present in the bitstream.

NOTE—An instantaneous decoding refresh (IDR) picture havingnal_unit_type equal to IDR_N_LP does not have associated leadingpictures present in the bitstream. An IDR picture having nal_unit_typeequal to IDR_W_RADL does not have associated RASL pictures present inthe bitstream, but may have associated RADL pictures in the bitstream.

The value of nal_unit_type shall be the same for all VCL NAL units of asubpicture. A subpicture is referred to as having the same NAL unit typeas the VCL NAL units of the subpicture.

When any two subpictures in a picture have different NAL unit types, thevalue of sps_subpic_treated_as_pic_flag[ ] shall be equal to 1 for allsubpictures in the picture that contain at least one P or B slice.

For VCL NAL units of any particular picture, the following applies:

-   -   If pps_mixed_nalu_types_in_pic_flag is equal to 0, the value of        nal_unit_type shall be the same for all VCL NAL units of a        picture, and a picture or a PU is referred to as having the same        NAL unit type as the coded slice NAL units of the picture or PU.    -   Otherwise (pps_mixed_nalu_types_in_pic_flag is equal to 1), the        following applies:        -   The picture shall have at least two subpictures.        -   VCL NAL units of the picture shall have two or more            different nal_unit_type values.        -   There shall be no VCL NAL unit of the picture that has            nal_unit_type_equal to GDR_NUT.        -   When the VCL NAL units of at least one subpicture of the            picture have a particular value of nal_unit_type equal to            IDR_W_RADL, IDR_N_LP, or CRA_NUT, the VCL NAL units of other            subpictures in the picture shall all have nal_unit_type            equal to TRAIL_NUT.

When vps_max_tid_il_ref_pics_plus1[i][j] is equal to 0 for j equal toGeneralLayerIdx[nuh_layer_id] and any value of i in the range of j+1 tovps_max_layers_minus1, inclusive, the current picture shall not haveboth VCL NAL units with a particular value of nal_unit_type equal toIDR_W_RADL, IDR_N_LP, or CRA_NUT and VCL NAL units with nal_unit_typeequal to a different value than that particular value.

It is a requirement of bitstream conformance that the followingconstraints apply:

-   -   When a picture is a leading picture of an IRAP picture, it shall        be a RADL or RASL picture.    -   When a subpicture is a leading subpicture of an IRAP subpicture,        it shall be a RADL or RASL subpicture.    -   When a picture is not a leading picture of an IRAP picture, it        shall not be a RADL or RASL picture.    -   When a subpicture is not a leading subpicture of an IRAP        subpicture, it shall not be a RADL or RASL subpicture.    -   No RASL pictures shall be present in the bitstream that are        associated with an IDR picture.    -   No RASL subpictures shall be present in the bitstream that are        associated with an IDR subpicture.    -   No RADL pictures shall be present in the bitstream that are        associated with an IDR picture having nal_unit_type equal to        IDR_N_LP.        -   NOTE—It is possible to perform random access at the position            of an IRAP PU by discarding all PUs before the IRAP PU (and            to correctly decode the IRAP picture and all the subsequent            non-RASL pictures in decoding order), provided each            parameter set is available (either in the bitstream or by            external means not specified in this Specification) when it            is referenced.    -   No RADL subpictures shall be present in the bitstream that are        associated with an IDR subpicture having nal_unit_type equal to        IDR_N_LP.    -   Any picture, with nuh_layer_id equal to a particular value        layerId, that precedes an IRAP picture with nuh_layer_id equal        to layerId in decoding order shall precede the IRAP picture in        output order and shall precede any RADL picture associated with        the IRAP picture in output order.    -   Any subpicture, with nuh_layer_id equal to a particular value        layerId and subpicture index equal to a particular value        subpicIdx, that precedes, in decoding order, an IRAP subpicture        with nuh_layer_id equal to layerId and subpicture index equal to        subpicIdx shall precede, in output order, the IRAP subpicture        and all its associated RADL subpictures.    -   Any picture, with nuh_layer_id equal to a particular value        layerId, that precedes a recovery point picture with        nuh_layer_id equal to layerId in decoding order shall precede        the recovery point picture in output order.    -   Any subpicture, with nuh_layer_id equal to a particular value        layerId and subpicture index equal to a particular value        subpicIdx, that precedes, in decoding order, a subpicture with        nuh_layer_id equal to layerId and subpicture index equal to        subpicIdx in a recovery point picture shall precede that        subpicture in the recovery point picture in output order.    -   Any RASL picture associated with a CRA picture shall precede any        RADL picture associated with the CRA picture in output order.    -   Any RASL subpicture associated with a CRA subpicture shall        precede any RADL subpicture associated with the CRA subpicture        in output order.    -   Any RASL picture, with nuh_layer_id equal to a particular value        layerId, associated with a CRA picture shall follow, in output        order, any IRAP or GDR picture with nuh_layer_id equal to        layerId that precedes the CRA picture in decoding order.    -   Any RASL subpicture, with nuh_layer_id equal to a particular        value layerId and subpicture index equal to a particular value        subpicIdx, associated with a CRA subpicture shall follow, in        output order, any IRAP or GDR subpicture, with nuh_layer_id        equal to layerId and subpicture index equal to subpicIdx, that        precedes the CRA subpicture in decoding order.    -   If sps_field_seq_flag is equal to 0 and the current picture,        with nuh_layer_id equal to a particular value layerId, is a        leading picture associated with an IRAP picture, it shall        precede, in decoding order, all non-leading pictures that are        associated with the same IRAP picture. Otherwise, let picA and        picB be the first and the last leading pictures, in decoding        order, associated with an IRAP picture, respectively, there        shall be at most one non-leading picture with nuh_layer_id equal        to layerId preceding picA in decoding order, and there shall be        no non-leading picture with nuh_layer_id equal to layerId        between picA and picB in decoding order.    -   If sps_field_seq_flag is equal to 0 and the current subpicture,        with nuh_layer_id equal to a particular value layerId and        subpicture index equal to a particular value subpicIdx, is a        leading subpicture associated with an IRAP subpicture, it shall        precede, in decoding order, all non-leading subpictures that are        associated with the same IRAP subpicture. Otherwise, let subpicA        and subpicB be the first and the last leading subpictures, in        decoding order, associated with an IRAP subpicture,        respectively, there shall be at most one non-leading subpicture        with nuh_layer_id equal to layerId and subpicture index equal to        subpicIdx preceding subpicA in decoding order, and there shall        be no non-leading picture with nuh_layer_id equal to layerId and        subpicture index equal to subpicIdx between picA and picB in        decoding order.

It should be noted that generally, an Intra Random Access Point (IRAP)picture is a picture that does not refer to any pictures other thanitself for prediction in its decoding process. In JVET-R2001, an IRAPpicture may be a clean random access (CRA) picture or an instantaneousdecoder refresh (IDR) picture. In JVET-R2001, the first picture in thebitstream in decoding order must be an IRAP or a gradual decodingrefresh (GDR) picture. JVET-R2001 describes the concept of a leadingpicture, which is a picture that precedes the associated IRAP picture inoutput order. JVET-R2001 further describes the concept of a trailingpicture which is a non-IRAP picture that follows the associated IRAPpicture in output order. Trailing pictures associated with an IRAPpicture also follow the IRAP picture in decoding order. For IDRpictures, there are no trailing pictures that require reference to apicture decoded prior to the IDR picture. JVET-R2001 provides where aCRA picture may have leading pictures that follow the CRA picture indecoding order and contain inter picture prediction references topictures decoded prior to the CRA picture. Thus, when the CRA picture isused as a random access point these leading pictures may not bedecodable and are identified as random access skipped leading (RASL)pictures. The other type of picture that can follow an IRAP picture indecoding order and precede it in output order is the random accessdecodable leading (RADL) picture, which cannot contain references to anypictures that precede the IRAP picture in decoding order. A GDR picture,is a picture for which each VCL NAL unit has nal_unit_type equal toGDR_NUT. If the current picture is a GDR picture that is associated witha picture header which signals a syntax element recovery_poc_cnt andthere is a picture picA that follows the current GDR picture in decodingorder in the CLVS and that has PicOrderCntVal equal to thePicOrderCntVal of the current GDR picture plus the value ofrecovery_poc_cnt, the picture picA is referred to as the recovery pointpicture.

As provided in Table 2, a NAL unit may include a sequence parameter set(SPS) syntax structure. Table 3 illustrates the syntax structure of thevideo parameter set provided in JVET-R2001.

TABLE 3 seq_parameter_set_rbsp( ) { Descriptor  sps_seq_parameter_set_idu(4)  sps_video_parameter_set_id u(4)  sps_max_sublayers_minus1 u(3) sps_reserved_zero_4bits u(4)  sps_ptl_dpb_hrd_params_present_flag u(1) if( sps_ptl_dpb_hrd_params_present_flag )   profile_tier_level( 1,sps_max_sublayers_minus1 )  sps_gdr_enabled_flag u(1) sps_chroma_format_idc u(2)  sps_ref_pic_resampling_enabled_flag u(1) if( sps_ref pic_resampling_enabled_flag )  sps_res_change_in_clvs_allowed_flag u(1) sps_pic_width_max_in_luma_samples ue(v) sps_pic_height_max_in_luma_samples ue(v)  sps_conformance_window_flagu(1)  if( sps_conformance_window_flag ) {   sps_conf_win_left_offsetue(v)   sps_conf_win_right_offset ue(v)   sps_conf_win_top_offset ue(v)  sps_conf_win_bottom_offset ue(v)  }  sps_log2_ctu_size_minus5 u(2) sps_subpic_info_present_flag u(1)  if( sps_subpic_info_present_flag ) {  sps_num_subpics_minus1 ue(v)   if( sps_num_subpics_minus1 > 0 )   sps_independent_subpics_flag u(1)   for( i = 0;sps_num_subpics_minus1 > 0 && i <= sps_num_subpics_minus1; i++ ) {   if( i > 0 && sps_pic_width_max_in_luma_samples > CtbSizeY )    sps_subpic_ctu_top_left_x[ i ] u(v)    if( i > 0 &&sps_pic_height_max_in_luma_samples > CtbSizeY ) {    sps_subpic_ctu_top_left_y[ i ] u(v)    if( i <sps_num_subpics_minus1 &&      sps_pic_width_max_in_luma_samples >CtbSizeY )     sps_subpic_width_minus1[ i ] u(v)    if( i <sps_num_subpics_minus1 &&      sps_pic_height_max_in_luma_samples >CtbSizeY )     sps_subpic_height_minus1[ i ] u(v)    if(!sps_independent_subpics_flag) {     sps_subpic_treated_as_pic_flag[ i ]u(1)     sps_loop_filter_across_subpic_enabled_flag[ i ] u(1)    }   }  sps_subpic_id_len_minus1 ue(v)  sps_subpic_id_mapping_explicitly_signalled_flag u(1)   if(sps_subpic_id_mapping_explicitly_signalled_flag ) {   sps_subpic_id_mapping_present_flag u(1)    if(sps_subpic_id_mapping_present_flag )     for( i = 0; i <=sps_num_subpics_minus1; i++ )      sps_subpic_id[ i ] u(v)   }  } sps_bit_depth_minus8 ue(v)  sps_entropy_coding_sync_enabled_flag u(1) sps_entry_point_offsets_present_flag u(1) sps_log2_max_pic_order_cnt_lsb_minus4 u(4)  sps_poc_msb_cycle_flag u(1) if( sps_poc_msb_cycle_flag )   sps_poc_msb_cycle_len_minus1 ue(v) sps_num_extra_ph_bits_bytes u(2)  extra_ph_bits_struct(sps_num_extra_ph_bits_bytes )  sps_num_extra_sh_bits_bytes u(2) extra_sh_bits_struct( sps_num_extra_sh_bits_bytes )  if(sps_ptl_dpb_hrd_params_present_flag ) {   if( sps_max_sublayers_minus1 >0 )    sps_sublayer_dpb_params_flag u(1)   dpb_parameters(sps_max_sublayers_minus1, sps_sublayer_dpb_params_flag )  }  if(ChromaArrayType != 0 )   sps_qtbtt_dual_tree_intra_flag u(1) sps_log2_min_luma_coding_block_size_minus2 ue(v) sps_partition_constraints_override_enabled_flag u(1) sps_log2_diff_min_qt_min_eb_intra_slice_luma ue(v) sps_max_mtt_hierarchy_depth_intra_slice_luma ue(v)  if(sps_max_mtt_hierarchy_depth_intra_slice_luma != 0 ) {  sps_log2_diff_max_bt_min_qt_intra_slice_luma ue(v)  sps_log2_diff_max_tt_min_qt_intra_slice_luma ue(v)  } sps_log2_diff_min_qt_min_cb_inter_slice ue(v) sps_max_mtt_hierarchy_depth_inter_slice ue(v)  if(sps_max_mtt_hierarchy_depth_inter_slice != 0 ) {  sps_log2_diff_max_bt_min_qt_inter_slice ue(v)  sps_log2_diff_max_tt_min_qt_inter_slice ue(v)  }  if(sps_qtbtt_dual_tree_intra_flag ) {  sps_log2_diff_min_qt_min_eb_intra_slice_chroma ue(v)  sps_max_mtt_hierarchy_depth_intra_slice_chroma ue(v)   if(sps_max_mtt_hierarchy_depth_intra_slice_chroma != 0 ) {   sps_log2_diff_max_bt_min_qt_intra_slice_chroma ue(v)   sps_log2_diff_max_tt_min_qt_intra_slice_chroma ue(v)   }  }  if(CtbSizeY > 32 )   sps_max_luma_transform_size_64_flag u(1)  if(ChromaArrayType != 0 ) {   sps_joint_cbcr_enabled_flag u(1)  sps_same_qp_table_for_chroma_flag u(1)   numQpTables =sps_same_qp_table_for_chroma_flag ? 1 :     (sps_joint_cbcr_enabled_flag ? 3 : 2 )   for( i = 0; i < numQpTables; i++) {    sps_qp_table_start_minus26[ i ] se(v)   sps_num_points_in_qp_table_minus1[ i ] ue(v)    for( j = 0; j <=sps_num_points_in_qp_table_minus1[ i ]; j++ ) {    sps_delta_qp_in_val_minus1[ i ][ j ] ue(v)    sps_delta_qp_diff_val[ i ][ j ] ue(v)    }   }  } sps_sao_enabled_flag u(1)  sps_alf_enabled_flag u(1)  if(sps_alf_enabled_flag && ChromaArrayType ! = 0 )   sps_ccalf_enabled_flagu(1)  sps_transform_skip_enabled_flag u(1)  if(sps_transform_skip_enabled_flag ) {  sps_log2_transform_skip_max_size_minus2 ue(v)   sps_bdpcm_enabled_flagu(1)  }  sps_weighted_pred_flag u(1)  sps_weighted_bipred_flag u(1) sps_long_term_ref_pics_flag u(1)  if( sps_video_parameter_set_id > 0 )  sps_inter_layer_ref_pics_present_flag u(1)  sps_idr_rpl_present_flagu(1)  sps_rpl1_same_as_rpl0_flag u(1)  for( i = 0; i <sps_rpl1_same_as_rpl0_flag ? 1 : 2; i++ ) {   sps_num_ref_pic_lists[ i ]ue(v)   for( j = 0; j < sps_num_ref pic_lists[ i ]; j++)    refpic_list_struct( i, j )  }  sps_ref_wraparound_enabled_flag u(1) sps_temporal_mvp_enabled_flag u(1)  if( sps_temporal_mvp_enabled_flag )  sps_sbtmvp_enabled_flag u(1)  sps_amvr_enabled_flag u(1) sps_bdof_enabled_flag u(1)  if( sps_bdof_enabled_flag )  sps_bdof_control_present_in_ph_flag u(1)  sps_smvd_enabled_flag u(1) sps_dmvr_enabled_flag u(1)  if( sps_dmvr_enabled_flag)  sps_dmvr_control_present_in_ph_flag u(1)  sps_mmvd_enabled_flag u(1) if( sps_mmvd_enabled_flag )   sps_mmvd_fullpel_only_flag u(1) sps_six_minus_max_num_merge_cand ue(v)  sps_sbt_enabled_flag u(1) sps_affine_enabled_flag u(1)  if( sps_affine_enabled_flag ) {  sps_five_minus_max_num_subblock_merge_cand ue(v)  sps_affine_type_flag u(1)   if( sps_amvr_enabled_flag )   sps_affine_amvr_enabled_flag u(1)   sps_affine_prof_enabled_flag u(1)  if( sps_affine_prof_enabled_flag )   sps_prof_control_present_in_ph_flag u(1)  }  sps_bcw_enabled_flagu(1)  sps_ciip_enabled_flag u(1)  if( MaxNumMergeCand >= 2 ) {  sps_gpm_enabled_flag u(1)   if( sps_gpm_enabled_flag &&MaxNumMergeCand >= 3 )    sps_max_num_merge_cand_minus_max_num_gpm_candue(v)  }  sps_log2_parallel_merge_level_minus2 ue(v) sps_isp_enabled_flag u(1)  sps_mrl_enabled_flag u(1) sps_mip_enabled_flag u(1)  if( ChromaArrayType != 0 )  sps_cclm_enabled_flag u(1)  if( sps_chroma_format_idc = = 1 ) {  sps_chroma_horizontal_collocated_flag u(1)  sps_chroma_vertical_collocated_flag u(1)  }  sps_mts_enabled_flag u(1) if( sps_mts_enabled_flag ) {   sps_explicit_mts_intra_enabled_flag u(1)  sps_explicit_mts_inter_enabled_flag u(1)  }  sps_palette_enabled_flagu(1)  if( ChromaArrayType = = 3 && !sps_max_luma_transform_size_64_flag)   sps_act_enabled_flag u(1)  if( sps_transform_skip_enabled_flag | |sps_palette_enabled_flag )  sps_internal_bit_depth_minus_input_bit_depth ue(v) sps_ibc_enabled_flag u(1)  if( sps_ibc_enabled_flag )  sps_six_minus_max_num_ibc_merge_cand ue(v)  sps_lmcs_enabled_flag u(1) sps_lfnst_enabled_flag u(1)  sps_ladf_enabled_flag u(1)  if(sps_ladf_enabled_flag ) {   sps_num_ladf_intervals_minus2 u(2)  sps_ladf_lowest_interval_qp_offset se(v)   for( i = 0; i <sps_num_ladf_intervals_minus2 + 1; i++ ) {    sps_ladf_qp_offset[ i ]se(v)    sps_ladf_delta_threshold_minus1[ i ] ue(v)   }  } sps_explicit_scaling_list_enabled_flag u(1)  if( sps_lfnst_enabled_flag&& sps_explicit_scaling_list_enabled_flag ) sps_scaling_matrix_for_lfnst_disabled_flag u(1) if(sps_act_enabled_flag && sps_explicit_scaling_list_enabled_flag ) sps_scaling_matrix_for_alternative_colour_space_disabled_flag u(1) if(sps_scaling_matrix_for_alternative_colour_space_disabled_flag ) sps_scaling_matrix_designated_colour_space_flag u(1) sps_dep_quant_enabled_flag u(1)  if( !sps_dep_quant_enabled_flag )  sps_sign_data_hiding_enabled_flag u(1) sps_virtual_boundaries_enabled_flag u(1)  if(sps_virtual_boundaries_enabled_flag ) {  sps_virtual_boundaries_present_flag u(1)   if(sps_virtual_boundaries_present_flag ) {   sps_num_ver_virtual_boundaries u(2)    for( i = 0; i <sps_num_ver_virtual_boundaries; i++ )     sps_virtual_boundary_pos_x[ i] ue(v)    sps_num_hor_virtual_boundaries u(2)    for( i = 0; i <sps_num_hor_virtual_boundaries; i++ )     sps_virtual_boundary_pos_y[ i] ue(v)   }  }  if( sps_ptl_dpb_hrd_params_present_flag ) {  sps_general_hrd_params_present_flag u(1)   if(sps_general_hrd_params_present_flag ) {    general_hrd_parameters( )   if( sps_max_sublayers_minus1 > 0 )    sps_sublayer_cpb_params_present_flag u(1)    firstSubLayer =sps_sublayer_cpb_params_present_flag ? 0 :     sps_max_sublayers_minus1   ols_hrd_parameters( firstSubLayer, sps_max_sublayers_minus1 )   }  } sps_field_seq_flag u(1)  sps_vui_parameters_present_flag u(1)  if(sps_vui_parameters_present_flag )   vui_parameters( ) /* Specified inITU-T H.SEI | ISO/IEC 23002-7 */  sps_extension_flag u(1)  if(sps_extension_flag )   while( more_rbsp_data( ) )   sps_extension_data_flag u(1)  rbsp_trailing_bits( ) }

With respect to Table 3, JVET-R2001 provides the following semantics:

An SPS RBSP shall be available to the decoding process prior to it beingreferenced, included in at least one AU with TemporalId equal to 0 orprovided through external means.

All SPS NAL units with a particular value of sps_seq_parameter_set_id ina CVS shall have the same content.

sps_seq_parameter_set_id provides an identifier for the SPS forreference by other syntax elements.

SPS NAL units, regardless of the nuh_layer_id values, share the samevalue space of sps_seq_parameter_set_id.

Let spsLayerId be the value of the nuh_layer_id of a particular SPS NALunit, and vclLayerId be the value of the nuh_layer_id of a particularVCL NAL unit. The particular VCL NAL unit shall not refer to theparticular SPS NAL unit unless spsLayerId is less than or equal tovclLayerId and all OLSs specified by the VPS that contain the layer withnuh_layer_id equal to vclLayerId also contain the layer withnuh_layer_id equal to spslayerId.

sps_video_parameter_set_id, when greater than 0, specifies the value ofvps_video_parameter_set_id for the VPS referred to by the SPS.

When sps_video_parameter_set_id is equal to 0, the following applies:

-   -   The SPS does not refer to a VPS, and no VPS is referred to when        decoding each CLVS referring to the SPS.    -   The value of vps_max_layers_minus1 is inferred to be equal to 0.    -   The value of vps_max_sublayers_minus1 is inferred to be equal to        6.    -   The CVS shall contain only one layer (i.e., all VCL NAL unit in        the CVS shall have the same value of nuh_layer_id).    -   The value of GeneralLayerIdx[nuh_layer_id] is inferred to be        equal to 0.    -   The value of        vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id] ] is        inferred to be equal to 1.

When vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id] ] is equalto 1, the SPS referred to by a CLVS with a particular nuh_layer_id valuenuhLayerId shall have nuh_layer_id equal to nuhLayerId.

The value of sps_video_parameter_set_id shall be the same in all SPSsthat are referred to by CLVSs in a CVS.

sps_max_sublayers_minus1 plus 1 specifies the maximum number of temporalsublayers that may be present in each CLVS referring to the SPS. Thevalue of sps_max_sublayers_minus1 shall be in the range of 0 tovps_max_sublayers_minus1, inclusive.

sps_reserved_zero_4 bits shall be equal to 0 in bitstreams conforming tothis version of this Specification. Other values for sps_reserved_zero_4bits are reserved for future use by ITU-T|ISO/IEC.

sps_ptl_dpb_hrd_params_present_flag equal to 1 specifies that aprofile_tier_level( ) syntax structure and a dpb_parameters( ) syntaxstructure are present in the SPS, and a general_hrd_parameters( ) syntaxstructure and an ols_hrd_parameters( ) syntax structure may also bepresent in the SPS. sps_ptl_dpb_hrd_params_present_flag equal to 0specifies that none of these four syntax structures is present in theSPS.

When sps_video_parameter_set_id is greater than 0 and there is an OLSthat contains only one layer with nuh_layer_id equal to the nuh_layer_idof the SPS, or when sps_video_parameter_set_id is equal to 0, the valueof sps_ptl_dpb_hrd_params_present_flag shall be equal to 1.

sps_gdr_enabled_flag equal to 1 specifies that GDR pictures are enabledand may be present in CLVS. sps_gdr_enabled_flag equal to 0 specifiesthat GDR pictures are disabled and not present in CLVS.

sps_chroma_format_idc specifies the chroma sampling relative to the lumasampling as specified.

When sps_video_parameter_set_id is greater than 0 and the SPS isreferenced by a layer that is included in the i-th multi-layer OLSspecified by the VPS for any i in the range of 0 to NumMultiLayerOlss−1,inclusive, it is a requirement of bitstream conformance that the valueof sps_chroma_format_idc shall be less than or equal to the value ofvps_ols_dpb_chroma_format[i].

sps_separate_colour_plane_flag equal to 1 specifies that the threecolour components of the 4:4:4 chroma format are coded separately.sps_separate_colour_plane_flag equal to 0 specifies that the colourcomponents are not coded separately. When sps_separate_colour_plane_flagis not present, it is inferred to be equal to 0. Whensps_separate_colour_plane_flag is equal to 1, the coded picture consistsof three separate components, each of which consists of coded samples ofone colour plane (Y, Cb, or Cr) and uses the monochrome coding syntax.In this case, each colour plane is associated with a specificsh_colour_plane_id value.

-   -   NOTE—There is no dependency in decoding processes between the        colour planes having different sh_colour_plane_id values. For        example, the decoding process of a monochrome picture with one        value of sh_colour_plane_id does not use any data from        monochrome pictures having different values of        sh_colour_plane_id for inter prediction.

Depending on the value of sps_separate_colour_plane_flag, the value ofthe variable ChromaArrayType is assigned as follows:

-   -   If sps_separate_colour_plane_flag is equal to 0, ChromaArrayType        is set equal to sps_chroma_format_idc.    -   Otherwise (sps_separate_colour_plane_flag is equal to 1),        ChromaArrayType is set equal to 0.

sps_ref_pic_resampling_enabled_flag equal to 1 specifies that referencepicture resampling is enabled and one or more slices of pictures in theCLVS may refer to a reference picture with a different spatialresolution in an active entry of a reference picture list.sps_ref_pic_resampling_enabled_flag equal to 0 specifies that referencepicture resampling is disabled and no slice of pictures in the CLVSrefers to a reference picture with a different spatial resolution in anactive entry of a reference picture list.

-   -   NOTE—When sps_ref_pic_resampling_enabled_flag is equal to 1, for        a current picture the reference picture with a different spatial        resolution may either belong to the same layer or a different        layer than the layer containing the current picture.

sps_res_change_in_clvs_allowed_flag equal to 1 specifies that thepicture spatial resolution may change within a CLVS referring to theSPS. sps_res_change_in_clvs_allowed_flag equal to 0 specifies that thepicture spatial resolution does not change within any CLVS referring tothe SPS. When not present, the value ofsps_res_change_in_clvs_allowed_flag is inferred to be equal to 0.

sps_pic_width_max_in_luma_samples specifies the maximum width, in unitsof luma samples, of each decoded picture referring to the SPS.sps_pic_width_max_in_luma_samples shall not be equal to 0 and shall bean integer multiple of Max(8, MinCbSizeY).

When sps_video_parameter_set_id is greater than 0 and the SPS isreferenced by a layer that is included in the i-th multi-layer OLSspecified by the VPS for any i in the range of 0 to NumMultiLayerOlss−1,inclusive, it is a requirement of bitstream conformance that the valueof sps_pic_width_max_in_luma_samples shall be less than or equal to thevalue of vps_ols_dpb_pic_width[i].

sps_pic_height_max_in_luma_samples specifies the maximum height, inunits of luma samples, of each decoded picture referring to the SPS.sps_pic_height_max_in_luma_samples shall not be equal to 0 and shall bean integer multiple of Max(8, MinCbSizeY).

When sps_video_parameter_set_id is greater than 0 and the SPS isreferenced by a layer that is included in the i-th multi-layer OLSspecified by the VPS for any i in the range of 0 to NumMultiLayerOlss−1,inclusive, it is a requirement of bitstream conformance that the valueof sps_pic_height_max_in_luma_samples shall be less than or equal to thevalue of vps_ols_dpb_pic_height[i].

sps_conformance_window_flag equal to 1 indicates that the conformancecropping window offset parameters follow next in the SPS.sps_conformance_window_flag equal to 0 indicates that the conformancecropping window offset parameters are not present in the SPS.

sps_conf_win_left_offset, sps_conf_win_right_offset,sps_conf_win_top_offset, and sps_conf_win_bottom_offset specify thecropping window that is applied to pictures withpps_pic_width_in_luma_samples equal to sps_pic_width_max_in_luma_samplesand pps_pic_height_in_luma_samples equal tosps_pic_height_max_in_luma_samples. When sps_conformance_window_flag isequal to 0, the values of sps_conf_win_left_offset,sps_conf_win_right_offset, sps_conf_win_top_offset, andsps_conf_win_bottom_offset are inferred to be equal to 0.

The conformance cropping window contains the luma samples withhorizontal picture coordinates from SubWidthC*sps_conf_win_left_offsettosps_pic_width_max_in_luma_samples−(SubWidthC*sps_conf_win_right_offset+1)and vertical picture coordinates from SubHeightC*sps_conf_win_top_offsettosps_pic_height_max_in_luma_samples−(SubHeightC*sps_conf_win_bottom_offset+1),inclusive.

The value ofSubWidthC*(sps_conf_win_left_offset+sps_conf_win_right_offset) shall beless than sps_pic_width_max_in_luma_samples, and the value ofSubHeightC*(sps_conf_win_top_offset+sps_conf_win_bottom_offset) shall beless than sps_pic_height_max_in_luma_samples.

When ChromaArrayType is not equal to 0, the corresponding specifiedsamples of the two chroma arrays are the samples having picturecoordinates (x/SubWidthC, y/SubHeightC), where (x, y) are the picturecoordinates of the specified luma samples.

-   -   NOTE—The conformance cropping window offset parameters are only        applied at the output. All internal decoding processes are        applied to the uncropped picture size.

sps_log_2_ctu_size_minus5 plus 5 specifies the luma coding tree blocksize of each CTU. The value of sps_log_2_ctu_size_minus5 shall be in therange of 0 to 2, inclusive. The value 3 for sps_log_2_ctu_size_minus5 isreserved for future use by ITU-T|ISO/IEC.

The variables CtbLog2SizeY and CtbSizeY are derived as follows:CtbLog2SizeY=sps_log_2_ctu_size_minus5+5CtbSizeY=1<<CtbLog2SizeYsps_subpic_info_present_flag equal to 1 specifies that subpictureinformation is present for the CLVS and there may be one or more thanone subpicture in each picture of the CLVS. sps_subpic_info_present_flagequal to 0 specifies that subpicture information is not present for theCLVS and there is only one subpicture in each picture of the CLVS. Whensps_res_change_in_clvs_allowed_flag is equal to 1, the value ofsps_subpic_info_present_flag shall be equal to 0.

-   -   NOTE—When a bitstream is the result of a sub-bitstream        extraction process and contains only a subset of the subpictures        of the input bitstream to the sub-bitstream extraction process,        it might be required to set the value of        sps_subpic_info_present_flag equal to 1 in the RBSP of the SPSs.

sps_num_subpics_minus1 plus 1 specifies the number of subpictures ineach picture in the CLVS. The value of sps_num_subpics_minus1 shall bein the range of 0 to Ceil(sps_pic_width_max_in_luma_samplesCtbSizeY)*Ceil(sps_pic_height_max_in_luma_samples÷CtbSizeY)−1,inclusive. When not present, the value of sps_num_subpics_minus1 isinferred to be equal to 0.

sps_independent_subpics_flag equal to 1 specifies that all subpictureboundaries in the CLVS are treated as picture boundaries and there is noloop filtering across the subpicture boundaries.sps_independent_subpics_flag equal to 0 does not impose such aconstraint. When not present, the value of sps_independent_subpics_flagis inferred to be equal to 1.

sps_subpic_ctu_top_left_x[i] specifies horizontal position of top leftCTU of i-th subpicture in unit of CtbSizeY. The length of the syntaxelement isCeil(Log2((sps_pic_width_max_in_luma_samples+CtbSizeY−1)>>CtbLog2SizeY))bits. When not present, the value of sps_subpic_ctu_top_left_x[i] isinferred to be equal to 0.

sps_subpic_ctu_top_left_y[i] specifies vertical position of top left CTUof i-th subpicture in unit of CtbSizeY. The length of the syntax elementisCeil(Log2((sps_pic_height_max_in_luma_samples+CtbSizeY−1)>>CtbLog2SizeY))bits. When not present, the value of sps_subpic_ctu_top_left_y[i] isinferred to be equal to 0.

sps_subpic_width_minus1[i] plus 1 specifies the width of the i-thsubpicture in units of CtbSizeY. The length of the syntax element isCeil(Log2((sps_pic_width_max_in_luma_samples+CtbSizeY−1)>>CtbLog2SizeY))bits. When not present, the value of sps_subpic_width_minus1[i] isinferred to be equal to((sps_pic_width_max_in_luma_samples+CtbSizeY−1)>>CtbLog2SizeY)−sps_subpic_ctu_top_left_x[i]−1.

sps_subpic_height_minus1[i] plus 1 specifies the height of the i-thsubpicture in units of CtbSizeY. The length of the syntax element isCeil(Log2((sps_pic_height_max_in_luma_samples+CtbSizeY−1)>>CtbLog2SizeY))bits. When not present, the value of sps_subpic_height_minus1[i] isinferred to be equal to((sps_pic_height_max_in_luma_samples+CtbSizeY−1)>>CtbLog2SizeY)−sps_subpic_ctu_top_left_y[i]−1.

It is a requirement of bitstream conformance that the shapes of thesubpictures shall be such that each subpicture, when decoded, shall haveits entire left boundary and entire top boundary consisting of pictureboundaries or consisting of boundaries of previously decodedsubpictures.

For each subpicture with subpicture index i in the range of 0 tosps_num_subpics_minus1, inclusive, it is a requirement of bitstreamconformance that all of the following conditions are true:

-   -   The value of (sps_subpic_ctu_top_left_x[i]*CtbSizeY) shall be        less than        (sps_pic_width_max_in_luma_samples−sps_conf_win_right_offset*SubWidthC).    -   The value of        ((sps_subpic_ctu_top_left_x[i]+sps_subpic_width_minus1        [i]+1)*CtbSizeY) shall be greater than        (sps_conf_win_left_offset*SubWidthC).    -   The value of (sps_subpic_ctu_top_left_y[i]*CtbSizeY) shall be        less than        (sps_pic_height_max_in_luma_samples−sps_conf_win_bottom_offset*SubHeightC).    -   The value of        ((sps_subpic_ctu_top_left_y[i]+sps_subpic_height_minus1        [i]+1)*CtbSizeY) shall be greater than        (sps_conf_win_top_offset*SubHeightC).

sps_subpic_treated_as_pic_flag[i] equal to 1 specifies that the i-thsubpicture of each coded picture in the CLVS is treated as a picture inthe decoding process excluding in-loop filtering operations.sps_subpic_treated_as_pic_flag[i] equal to 0 specifies that the i-thsubpicture of each coded picture in the CLVS is not treated as a picturein the decoding process excluding in-loop filtering operations. When notpresent, the value of sps_subpic_treated_as_pic_flag[i] is inferred tobe equal to 1.

When sps_num_subpics_minus1 is greater than 0 andsps_subpic_treated_as_pic_flag[i] is equal to 1, for each CLVS of acurrent layer referring to the SPS, let targetAuSet be all the AUsstarting from the AU containing the first picture of the CLVS indecoding order, to the AU containing the last picture of the CLVS indecoding order, inclusive, it is a requirement of bitstream conformancethat all of the following conditions are true for the targetLayerSetthat consists of the current layer and all the layers that have thecurrent layer as a reference layer:

-   -   For each AU in targetAuSet, all pictures of the layers in        targetLayerSet shall have the same value of        pps_pic_width_in_luma_samples and the same value of        pps_pic_height_in_luma_samples.    -   All the SPSs referred to by the layers in targetLayerSet shall        have the same value of sps_num_subpics_minus1 and shall have the        same values of sps_subpic_ctu_top_left_x[j],        sps_subpic_ctu_top_left_y[j], sps_subpic_width_minus1[j],        sps_subpic_height_minus1[j], and        sps_subpic_treated_as_pic_flag[j], respectively, for each value        of j in the range of 0 to sps_num_subpics_minus1, inclusive.    -   For each AU in targetAuSet, all pictures of the layers in        targetLayerSet shall have the same value of SubpicIdVal[j] for        each value of j in the range of 0 to sps_num_subpics_minus1,        inclusive.

sps_loop_filter_across_subpic_enabled_flag[i] equal to 1 specifies thatin-loop filtering operations across subpicture boundaries is enabled andmay be performed across the boundaries of the i-th subpicture in eachcoded picture in the CLVS. sps_loop_filter_across_subpic_enabled_flag[i]equal to 0 specifies that in-loop filtering operations across subpictureboundaries is disabled and are not performed across the boundaries ofthe i-th subpicture in each coded picture in the CLVS. When not present,the value of sps_loop_filter_across_subpic_enabled_pic_flag[i] isinferred to be equal to 0.

sps_subpic_id_len_minus1 plus 1 specifies the number of bits used torepresent the syntax element sps_subpic_id[i], the syntax elementspps_subpic_id[i], when present, and the syntax element sh_subpic_id,when present. The value of sps_subpic_id_len_minus1 shall be in therange of 0 to 15, inclusive. The value of1<<(sps_subpic_id_len_minus1+1) shall be greater than or equal tosps_num_subpics_minus1+1.

sps_subpic_id_mapping_explicitly_signalled_flag equal to 1 specifiesthat the subpicture ID mapping is explicitly signalled, either in theSPS or in the PPSs referred to by coded pictures of the CLVS.sps_subpic_id_mapping_explicitly_signalled_flag equal to 0 specifiesthat the subpicture ID mapping is not explicitly signalled for the CLVS.When not present, the value ofsps_subpic_id_mapping_explicitly_signalled_flag is inferred to be equalto 0.

sps_subpic_id_mapping_present_flag equal to 1 specifies that thesubpicture ID mapping is signalled in the SPS whensps_subpic_id_mapping_explicitly_signalled_flag is equal to 1.sps_subpic_id_mapping_present_flag equal to 0 specifies that subpictureID mapping is signalled in the PPSs referred to by coded pictures of theCLVS when sps_subpic_id_mapping_explicitly_signalled_flag is equal to 1.

sps_subpic_id[i] specifies the subpicture ID of the i-th subpicture. Thelength of the sps_subpic_id[i] syntax element issps_subpic_id_len_minus1+1 bits.

sps_bit_depth_minus8 specifies the bit depth of the samples of the lumaand chroma arrays, BitDepth, and the value of the luma and chromaquantization parameter range offset, QpBdOffset, as follows:BitDepth=8+sps_bit_depth_minus8QpBdOffset=6*sps_bit_depth_minus8

sps_bit_depth_minus8 shall be in the range of 0 to 8, inclusive.

When sps_video_parameter_set_id is greater than 0 and the SPS isreferenced by a layer that is included in the i-th multi-layer OLSspecified by the VPS for any i in the range of 0 to NumMultiLayerOlss−1,inclusive, it is a requirement of bitstream conformance that the valueof sps_bit_depth_minus8 shall be less than or equal to the value ofvps_ols_dpb_bitdepth_minus8[i].

sps_entropy_coding_sync_enabled_flag equal to 1 specifies that aspecific synchronization process for context variables is invoked beforedecoding the CTU that includes the first CTB of a row of CTBs in eachtile in each picture referring to the SPS, and a specific storageprocess for context variables is invoked after decoding the CTU thatincludes the first CTB of a row of CTBs in each tile in each picturereferring to the SPS. sps_entropy_coding_sync_enabled_flag equal to 0specifies that no specific synchronization process for context variablesis required to be invoked before decoding the CTU that includes thefirst CTB of a row of CTBs in each tile in each picture referring to theSPS, and no specific storage process for context variables is requiredto be invoked after decoding the CTU that includes the first CTB of arow of CTBs in each tile in each picture referring to the SPS.

-   -   NOTE—When sps_entropy_coding_sync_enabled_flag is equal to 1,        the so-called wavefront parallel processing (WPP) is enabled.

sps_entry_point_offsets_present_flag equal to 1 specifies thatsignalling for entry point offsets for tiles or tile-specific CTU rowsmay be present in the slice headers of pictures referring to the SPS.sps_entry_point_offsets_present_flag equal to 0 specifies thatsignalling for entry point offsets for tiles or tile-specific CTU rowsare not present in the slice headers of pictures referring to the SPS.

sps_log_2_max_pic_order_cnt_lsb_minus4 specifies the value of thevariable MaxPicOrderCntLsb that is used in the decoding process forpicture order count as follows:MaxPicOrderCntLsb=2^((sps_log2_max_pic_order_cnt_lsb_minus4+4))

The value of sps_log2_max_pic_order_cnt_lsb_minus4 shall be in the rangeof 0 to 12, inclusive.

sps_poc_msb_cycle_flag equal to 1 specifies that theph_poc_msb_cycle_present_flag syntax element is present in PHs referringto the SPS. sps_poc_msb_cycle_flag equal to 0 specifies that theph_poc_msb_cycle_present_flag syntax element is not present in PHsreferring to the SPS.

sps_poc_msb_cycle_len_minus1 plus 1 specifies the length, in bits, ofthe ph_poc_msb_cycle_val syntax elements, when present in the PHsreferring to the SPS. The value of sps_poc_msb_cycle_len_minus1 shall bein the range of 0 to 32−sps_log_2_max_pic_order_cnt_lsb_minus4-5,inclusive.

sps_num_extra_ph_bits_bytes specifies the number of bytes of extra bitsin the PH syntax structure for coded pictures referring to the SPS. Thevalue of sps_num_extra_ph_bits_bytes shall be equal to 0 in bitstreamsconforming to this version of this Specification. Although the value ofsps_num_extra_ph_bits_bytes is required to be equal to 0 in this versionof this Specification, decoder conforming to this version of thisSpecification shall allow the value of sps_num_extra_ph_bits_bytes equalto 1 or 2 to appear in the syntax.

sps_num_extra_sh_bits_bytes specifies the number of bytes of extra bitsin the slice headers for coded pictures referring to the SPS. The valueof sps_num_extra_sh_bits_bytes shall be equal to 0 in bitstreamsconforming to this version of this Specification. Although the value ofsps_num_extra_sh_bits_bytes is required to be equal to 0 in this versionof this Specification, decoder conforming to this version of thisSpecification shall allow the value of sps_num_extra_sh_bits_bytes equalto 1 or 2 to appear in the syntax.

sps_sublayer_dpb_params_flag is used to control the presence ofmax_dec_pic_buffering_minus1[i], max_num_reorder_pics[i], andmax_latency_increase_plus1[i] syntax elements in the dpb_parameters( )syntax structure in the SPS. When not present, the value ofsps_sub_dpb_params_info_present_flag is inferred to be equal to 0.

sps_qtbtt_dual_tree_intra_flag equal to 1 specifies that, for I slices,each CTU is split into coding units with 64×64 luma samples using animplicit quadtree split, and these coding units are the root of twoseparate coding_tree syntax structure for luma and chroma.sps_qtbtt_dual_tree_intra_flag equal to 0 specifies separate coding_treesyntax structure is not used for I slices. Whensps_qtbtt_dual_tree_intra_flag is not present, it is inferred to beequal to 0.

sps_log2_min_luma_coding_block_size_minus2 plus 2 specifies the minimumluma coding block size. The value range ofsps_log2_min_luma_coding_block_size_minus2 shall be in the range of 0 toMin(4, sps_log_2_ctu_size_minus5+3), inclusive.

The variables MinCbLog2SizeY, MinCbSizeY, IbcBufWidthY, IbcBufWidthC andVsize are derived as follows:MinCbLog2SizeY=sps_log_2_min_luma_coding_block_size_minus2+2MinCbSizeY=1<<MinCbLog2SizeYIbcBufWidthY=256*128/CtbSizeYIbcBufWidthC=IbcBufWidthY/SubWidthCVSize=Min(64,CtbSizeY)

The value of MinCbSizeY shall less than or equal to VSize.

The variables CtbWidthC and CtbHeightC, which specify the width andheight, respectively, of the array for each chroma CTB, are derived asfollows:

-   -   If sps_chroma_format_idc is equal to 0 (monochrome) or        sps_separate_colour_plane_flag is equal to 1, CtbWidthC and        CtbHeightC are both equal to 0.    -   Otherwise, CtbWidthC and CtbHeightC are derived as follows:        CtbWidthC=CtbSizeY/SubWidthC        CtbHeightC=CtbSizeY/SubHeightC

For log2BlockWidth ranging from 0 to 4 and for log2BlockHeight rangingfrom 0 to 4, inclusive, the up-right diagonal scan order arrayinitialization process as specified is invoked with 1<<log2BlockWidthand 1<<log2BlockHeight as inputs, and the output is assigned toDiagScanOrder[log2BlockWidth][log2BlockHeight].

For log2BlockWidth ranging from 0 to 6 and for log2BlockHeight rangingfrom 0 to 6, inclusive, the horizontal and vertical traverse scan orderarray initialization process as specified is invoked with1<<log2BlockWidth and 1<<log2BlockHeight as inputs, and the output isassigned to HorTravScanOrder[log2BlockWidth][log2BlockHeight] andVerTravScanOrder[log2BlockWidth][log2BlockHeight].

sps_partition_constraints_override_enabled_flag equal to 1 specifies thepresence of ph_partition_constraints_override_flag in PHs referring tothe SPS. sps_partition_constraints_override_enabled_flag equal to 0specifies the absence of ph_partition_constraints_override_flag in PHsreferring to the SPS.

sps_log_2_diff_min_qt_min_cb_intra_slice_luma specifies the defaultdifference between the base 2 logarithm of the minimum size in lumasamples of a luma leaf block resulting from quadtree splitting of a CTUand the base 2 logarithm of the minimum coding block size in lumasamples for luma CUs in slices with sh_slice_type equal to 2 (I)referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault difference can be overridden by ph_log_2_diff_min_qt_min_cb_lumapresent in PHs referring to the SPS. The value ofsps_log_2_diff_min_qt_min_cb_intra_slice_luma shall be in the range of 0to Min(6, CtbLog2SizeY)−MinCbLog2SizeY, inclusive. The base 2 logarithmof the minimum size in luma samples of a luma leaf block resulting fromquadtree splitting of a CTU is derived as follows:MinQtLog2SizeIntraY=sps_log2_diff_min_qt_min_cb_intra_slice_luma+MinCbLog2SizeY

sps_max_mtt_hierarchy_depth_intra_slice_luma specifies the defaultmaximum hierarchy depth for coding units resulting from multi-type treesplitting of a quadtree leaf in slices with sh_slice_type equal to 2 (I)referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault maximum hierarchy depth can be overridden byph_max_mtt_hierarchy_depth_intra_slice_luma present in PHs referring tothe SPS. The value of sps_max_mtt_hierarchy_depth_intra_slice_luma shallbe in the range of 0 to 2*(CtbLog2SizeY−MinCbLog2SizeY), inclusive.

sps_log2_diff_max_bt_min_qt_intra_slice_luma specifies the defaultdifference between the base 2 logarithm of the maximum size (width orheight) in luma samples of a luma coding block that can be split using abinary split and the minimum size (width or height) in luma samples of aluma leaf block resulting from quadtree splitting of a CTU in sliceswith sh_slice_type equal to 2 (I) referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault difference can be overridden by ph_log_2_diff_max_bt_min_qt_lumapresent in PHs referring to the SPS. The value ofsps_log_2_diff_max_bt_min_qt_intra_slice_luma shall be in the range of 0to (sps_qtbtt_dual_tree_intra_flag ? Min(6,CtbLog2SizeY):CtbLog2SizeY)−MinQtLog2SizeIntraY, inclusive. Whensps_log_2_diff_max_bt_min_qt_intra_slice_luma is not present, the valueof sps_log_2_diff_max_bt_min_qt_intra_slice_luma is inferred to be equalto 0.

sps_log2_diff_max_tt_min_qt_intra_slice_luma specifies the defaultdifference between the base 2 logarithm of the maximum size (width orheight) in luma samples of a luma coding block that can be split using aternary split and the minimum size (width or height) in luma samples ofa luma leaf block resulting from quadtree splitting of a CTU in sliceswith sh_slice_type equal to 2 (I) referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault difference can be overridden by ph_log_2_diff_max_n_min_qt_lumapresent in PHs referring to the SPS. The value ofsps_log_2_diff_max_tt_min_qt_intra_slice_luma shall be in the range of 0to Min(6, CtbLog2SizeY)−MinQtLog2SizeIntraY, inclusive. Whensps_log_2_diff_max_n_min_qt_intra_slice_luma is not present, the valueof sps_log_2_diff_max_tt_min_qt_intra_slice_luma is inferred to be equalto 0.

sps_log_2_diff_min_qt_min_cb_inter_slice specifies the defaultdifference between the base 2 logarithm of the minimum size in lumasamples of a luma leaf block resulting from quadtree splitting of a CTUand the base 2 logarithm of the minimum luma coding block size in lumasamples for luma CUs in slices with sh_slice_type equal to 0 (B) or 1(P) referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault difference can be overridden by ph_log_2_diff_min_qt_min_cb_lumapresent in PHs referring to the SPS. The value ofsps_log_2_diff_min_qt_min_cb_inter_slice shall be in the range of 0 toMin(6, CtbLog2SizeY)−MinCbLog2SizeY, inclusive. The base 2 logarithm ofthe minimum size in luma samples of a luma leaf block resulting fromquadtree splitting of a CTU is derived as follows:MinQtLog2SizeInterY=sps_log2_diff_min_qt_min_cb_inter_slice+MinCbLog2SizeY

sps_max_mtt_hierarchy_depth_inter_slice specifies the default maximumhierarchy depth for coding units resulting from multi-type treesplitting of a quadtree leaf in slices with sh_slice_type equal to 0 (B)or 1 (P) referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault maximum hierarchy depth can be overridden byph_max_mtt_hierarchy_depth_inter_slice present in PHs referring to theSPS. The value of sps_max_mtt_hierarchy_depth_inter_slice shall be inthe range of 0 to 2*(CtbLog2SizeY−MinCbLog2SizeY), inclusive.

sps_log2_diff_max_bt_min_qt_inter_slice specifies the default differencebetween the base 2 logarithm of the maximum size (width or height) inluma samples of a luma coding block that can be split using a binarysplit and the minimum size (width or height) in luma samples of a lumaleaf block resulting from quadtree splitting of a CTU in slices withsh_slice_type equal to 0 (B) or 1 (P) referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault difference can be overridden by ph_log2_diff_max_bt_min_qt_lumapresent in PHs referring to the SPS. The value ofsps_log2_diff_max_bt_min_qt_inter_slice shall be in the range of 0 toCtbLog2SizeY−MinQtLog2SizeInterY, inclusive. Whensps_log2_diff_max_bt_min_qt_inter_slice is not present, the value ofsps_log2_diff_max_bt_min_qt_inter_slice is inferred to be equal to 0.

sps_log2_diff_max_tt_min_qt_inter_slice specifies the default differencebetween the base 2 logarithm of the maximum size (width or height) inluma samples of a luma coding block that can be split using a ternarysplit and the minimum size (width or height) in luma samples of a lumaleaf block resulting from quadtree splitting of a CTU in slices withsh_slice_type equal to 0 (B) or 1 (P) referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault difference can be overridden by ph_log2_diff_max_n_min_qt_lumapresent in PHs referring to the SPS. The value ofsps_log2_diff_max_tt_min_qt_inter_slice shall be in the range of 0 toMin(6, CtbLog2SizeY)−MinQtLog2SizeInterY, inclusive. Whensps_log2_diff_max_tt_min_qt_inter_slice is not present, the value ofsps_log2_diff_max_tt_min_qt_inter_slice is inferred to be equal to 0.

sps_log2_diff_min_qt_min_cb_intra_slice_chroma specifies the defaultdifference between the base 2 logarithm of the minimum size in lumasamples of a chroma leaf block resulting from quadtree splitting of achroma CTU with treeType equal to DUAL_TREE_CHROMA and the base 2logarithm of the minimum coding block size in luma samples for chromaCUs with treeType equal to DUAL_TREE_CHROMA in slices with sh_slice_typeequal to 2 (I) referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault difference can be overridden by ph_log2_diffmin_qt_min_cb_chroma present in PHs referring to the SPS. The value ofsps_log2_diff_min_qt_min_cb_intra_slice_chroma shall be in the range of0 to Min(6, CtbLog2SizeY)−MinCbLog2SizeY, inclusive. When not present,the value of sps_log2_diff_min_qt_min_cb_intra_slice_chroma is inferredto be equal to 0. The base 2 logarithm of the minimum size in lumasamples of a chroma leaf block resulting from quadtree splitting of aCTU with treeType equal to DUAL_TREE_CHROMA is derived as follows:MinQtLog2SizeIntraC=sps_log2_diff_min_qt_min_cb_intra_slice_chroma+MinCbLog2SizeY

sps_max_mtt_hierarchy_depth_intra_slice_chroma specifies the defaultmaximum hierarchy depth for chroma coding units resulting frommulti-type tree splitting of a chroma quadtree leaf with treeType equalto DUAL_TREE_CHROMA in slices with sh_slice_type equal to 2 (I)referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault maximum hierarchy depth can be overridden byph_max_mtt_hierarchy_depth_chroma present in PHs referring to the SPS.The value of sps_max_mtt_hierarchy_depth_intra_slice_chroma shall be inthe range of 0 to 2*(CtbLog2SizeY−MinCbLog2SizeY), inclusive. When notpresent, the value of sps_max_mtt_hierarchy_depth_intra_slice_chroma isinferred to be equal to 0.

sps_log2_diff_max_bt_min_qt_intra_slice_chroma specifies the defaultdifference between the base 2 logarithm of the maximum size (width orheight) in luma samples of a chroma coding block that can be split usinga binary split and the minimum size (width or height) in luma samples ofa chroma leaf block resulting from quadtree splitting of a chroma CTUwith treeType equal to DUAL_TREE_CHROMA in slices with sh_slice_typeequal to 2 (I) referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault difference can be overridden byph_log2_diff_max_bt_min_qt_chroma present in PHs referring to the SPS.The value of sps_log2_diff_max_bt_min_qt_intra_slice_chroma shall be inthe range of 0 to Min(6, CtbLog2SizeY)−MinQtLog2SizeIntraC, inclusive.When sps_log2_diff_max_bt_min_qt_intra_slice_chroma is not present, thevalue of sps_log2_diff_max_bt_min_qt_intra_slice_chroma is inferred tobe equal to 0.

sps_log2_diff_max_tt_min_qt_intra_slice_chroma specifies the defaultdifference between the base 2 logarithm of the maximum size (width orheight) in luma samples of a chroma coding block that can be split usinga ternary split and the minimum size (width or height) in luma samplesof a chroma leaf block resulting from quadtree splitting of a chroma CTUwith treeType equal to DUAL_TREE_CHROMA in slices with sh_slice_typeequal to 2 (I) referring to the SPS. Whensps_partition_constraints_override_enabled_flag is equal to 1, thedefault difference can be overridden byph_log2_diff_max_tt_min_qt_chroma present in PHs referring to the SPS.The value of sps_log2_diff_max_tt_min_qt_intra_slice_chroma shall be inthe range of 0 to Min(6, CtbLog2SizeY)−MinQtLog2SizeIntraC, inclusive.When sps_log2_diff_max_tt_min_qt_intra_slice_chroma is not present, thevalue of sps_log2_diff_max_tt_min_qt_intra_slice_chroma is inferred tobe equal to 0.

sps_max_luma_transform_size_64_flag equal to 1 specifies that themaximum transform size in luma samples is equal to 64.sps_max_luma_transform_size_64_flag equal to 0 specifies that themaximum transform size in luma samples is equal to 32. When not present,the value of sps_max_luma_transform_size_64_flag is inferred to be equalto 0.

The variables MinTbLog2SizeY, MaxTbLog2SizeY, MinTbSizeY, and MaxTbSizeYare derived as follows:MinTbLog2SizeY=2MaxTbLog2SizeY=sps_max_luma_transform_size_64_flag?6:5MinTbSizeY=1<<MinTbLog2SizeYMaxTbSizeY=1<<MaxTbLog2SizeY

sps_joint_eber_enabled_flag equal to 0 specifies that the joint codingof chroma residuals is disabled and not used in decoding of pictures inthe CLVS. sps_joint_cbcr_enabled_flag equal to 1 specifies that thejoint coding of chroma residuals is enabled and may be used in decodingof pictures in the CLVS. When not present, the value ofsps_joint_cbcr_enabled_flag is inferred to be equal to 0.

sps_same_qp_table_for_chroma_flag equal to 1 specifies that only onechroma QP mapping table is signalled and this table applies to Cb and Crresiduals and additionally to joint Cb-Cr residuals whensps_joint_cbcr_enabled_flag is equal to 1.sps_same_qp_table_for_chroma_flag equal to 0 specifies that chroma QPmapping tables, two for Cb and Cr, and one additional for joint Cb-Crwhen sps_joint_cbcr_enabled_flag is equal to 1, are signalled in theSPS. When not present, the value of sps_same_qp_table_for_chroma_flag isinferred to be equal to 1.

sps_qp_table_start_minus26[i] plus 26 specifies the starting luma andchroma QP used to describe the i-th chroma QP mapping table. The valueof sps_qp_table_start_minus26[i] shall be in the range of −26−QpBdOffsetto 36 inclusive. When not present, the value ofsps_qp_table_start_minus26[i] is inferred to be equal to 0.

sps_num_points_in_qp_table_minus1 [i] plus 1 specifies the number ofpoints used to describe the i-th chroma QP mapping table. The value ofsps_num_points_in_qp_table_minus1 [i] shall be in the range of 0 to63+QpBdOffset, inclusive. When not present, the value ofsps_num_points_in_qp_table_minus1 [0] is inferred to be equal to 0.

sps_delta_qp_in_val_minus1[i][j] specifies a delta value used to derivethe input coordinate of the j-th pivot point of the i-th chroma QPmapping table. When not present, the value ofsps_delta_qp_in_val_minus1[0][j] is inferred to be equal to 0.

sps_delta_qp_diff_val[i][j] specifies a delta value used to derive theoutput coordinate of the j-th pivot point of the i-th chroma QP mappingtable.

The i-th chroma QP mapping table ChromaQpTable[I] for I=0 . . .numQpTables−1 is derived as follows:

qpInVal[ i ][ 0 ] = sps_qp_table_start_minus26[ i ] + 26 qpOutVal[ i ][0 ] = qpInVal[ i ][ 0 ] for( j = 0; j <=sps_num_points_in_qp_table_minus1[ i ]; j++ ) {  qpInVal[ i ][ j + 1 ] =qpInVal[ i ][ j ] + sps_delta_qp_in_val_minus1[ i ][ j ] + 1  qpOutVal[i ][ j + 1 ] = qpOutVal[ i ][ j ] +   ( sps_delta_qp_in_val_minus1[ i ][j ] {circumflex over ( )} sps_delta_qp_diff_val[ i ][ j ] ) }ChromaQpTable[ i ][ qpInVal[ i ][ 0 ] ] = qpOutVal[ i ][ 0 ] for( k =qpInVal[ i ][ 0 ] − 1; k >= −QpBdOffset; k − − )  ChromaQpTable[ i ][ k] = Clip3( −QpBdOffset, 63, ChromaQpTable[ i ][ k + 1 ] − 1 ) for( j =0; j <= sps_num_points_in_qp_table_minus1[ i ]; j++ ) {  sh = (sps_delta_qp_in_val_minus1[ i ][ j ] + 1 ) >> 1  for( k = qpInVal[ i ][j ] + 1, m = 1; k <= qpInval[ i ][ j + 1 ]; k++, m++ )    ChromaQpTable[i ][ k ] = ChromaQpTable[ i ][ qpInVal[ i ][ j ] ] +     ( ( qpOutVal[ i][j + 1] − qpOutVal[ i ][ j ] ) * m + sh ) / (sps_delta_qp_in_val_minus1[ i ][ j ] + 1 ) } for( k = qpInVal[ i ][sps_num_points_in_qp_table_minus1[ i ] + 1 ] + 1; k <= 63; k++ ) ChromaQpTable[ i ][ k ] = Clip3( −QpBdOffset, 63, ChromaQpTable[ i ][ k− 1 ] + 1 )

When sps_same_qp_table_for_chroma_flag is equal to 1,ChromaQpTable[1][k] and ChromaQpTable[2][k] are set equal toChromaQpTable[0][k] for kin the range of −QpBdOffset to 63, inclusive.

It is a requirement of bitstream conformance that the values ofqpInVal[i][j] and qpOutVal[i][j] shall be in the range of −QpBdOffset to63, inclusive for i in the range of 0 to numQpTables−1, inclusive, and jin the range of 0 to sps_num_points_in_qp_table_minus1[i]+1, inclusive.

sps_sao_enabled_flag equal to 1 specifies that the sample adaptiveoffset process is enabled and may be applied to the reconstructedpicture after the deblocking filter process for the CLVS.sps_sao_enabled_flag equal to 0 specifies that the sample adaptiveoffset process is disabled and not applied to the reconstructed pictureafter the deblocking filter process for the CLVS.

sps_alf_enabled_flag equal to 0 specifies that the adaptive loop filteris disabled and not applied in decoding of pictures in the CLVS.sps_alf_enabled_flag equal to 1 specifies that the adaptive loop filteris enabled and may be applied in decoding of pictures in the CLVS.

sps_ccalf_enabled_flag equal to 0 specifies that the cross-componentadaptive loop filter is disabled and not applied in decoding of picturesin the CLVS. sps_ccalf_enabled_flag equal to 1 specifies that thecross-component adaptive loop filter is enabled and may be applied indecoding of pictures in the CLVS. When not present, the value ofsps_ccalf_enabled_flag is inferred to be equal to 0.

sps_transform_skip_enabled_flag equal to 1 specifies thattransform_skip_flag may be present in the transform unit syntax.sps_transform_skip_enabled_flag equal to 0 specifies thattransform_skip_flag is not present in the transform unit syntax.

sps_log2_transform_skip_max_size_minus2 specifies the maximum block sizeused for transform skip, and shall be in the range of 0 to 3, inclusive.

The variable MaxTsSize is set equal to1<<(sps_log2_transform_skip_max_size_minus2+2).

sps_bdpcm_enabled_flag equal to 1 specifies that intra_bdpcm_luma_flagand intra_bdpcm_chroma_flag may be present in the coding unit syntax forintra coding units. sps_bdpcm_enabled_flag equal to 0 specifies thatintra_bdpcm_luma_flag and intra_bdpcm_chroma_flag are not present in thecoding unit syntax for intra coding units. When not present, the valueof sps_bdpcm_enabled_flag is inferred to be equal to 0.

sps_weighted_pred_flag equal to 1 specifies that weighted prediction maybe applied to P slices referring to the SPS. sps_weighted_pred_flagequal to 0 specifies that weighted prediction is not applied to P slicesreferring to the SPS.

sps_weighted_bipred_flag equal to 1 specifies that explicit weightedprediction may be applied to B slices referring to the SPS.sps_weighted_bipred_flag equal to 0 specifies that explicit weightedprediction is not applied to B slices referring to the SPS.

sps_long_term_ref_pics_flag equal to 0 specifies that no LTRP is usedfor inter prediction of any coded picture in the CLVS.sps_long_term_ref_pics_flag equal to 1 specifies that LTRPs may be usedfor inter prediction of one or more coded pictures in the CLVS.

sps_inter_layer_ref_pics_present_flag equal to 0 specifies that no ILRPis used for inter prediction of any coded picture in the CLVS.sps_inter_layer_ref_pics_present_flag equal to 1 specifies that ILRPsmay be used for inter prediction of one or more coded pictures in theCLVS. When sps_video_parameter_set_id is equal to 0, the value ofsps_inter_layer_ref_pics_present_flag is inferred to be equal to 0. Whenvps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id] ] is equal to1, the value of sps_inter_layer_ref_pics_present_flag shall be equal to0.

sps_idr_rpl_present_flag equal to 1 specifies that reference picturelist syntax elements are present in slice headers of IDR pictures.sps_idr_rpl_present_flag equal to 0 specifies that reference picturelist syntax elements are not present in slice headers of IDR pictures.

sps_rpl1_same_as_rp10_flag equal to 1 specifies that the syntax elementsps_num_ref_pic_lists[1] and the syntax structure ref_pic_list_struct(1,rplsIdx) are not present and the following applies:

-   -   The value of sps_num_ref_pic_lists[1] is inferred to be equal to        the value of sps_num_ref_pic_lists[0].    -   The value of each of syntax elements in ref_pic_list_struct(1,        rplsIdx) is inferred to be equal to the value of corresponding        syntax element in ref_pic_list_struct(0, rplsIdx) for rplsIdx        ranging from 0 to sps_num_ref_pic_lists[0]−1.

sps_num_ref_pic_lists[i] specifies the number of theref_pic_list_struct(listIdx, rplsIdx) syntax structures with listIdxequal to i included in the SPS. The value of sps_num_ref_pic_lists[i]shall be in the range of 0 to 64, inclusive.

-   -   NOTE—For each value of listIdx (equal to 0 or 1), a decoder        should allocate memory for a total number of        sps_num_ref_pic_lists[i]+1 ref_pic_list_struct(listIdx, rplsIdx)        syntax structures since there may be one        ref_pic_list_struct(listIdx, rplsIdx) syntax structure directly        signalled in the slice headers of a current picture.

sps_ref_wraparound_enabled_flag equal to 1 specifies that horizontalwrap-around motion compensation is enabled and may be applied in interprediction when decoding pictures in the CLVS.sps_ref_wraparound_enabled_flag equal to 0 specifies that horizontalwrap-around motion compensation is disabled and not applied in interprediction when decoding pictures in the CLVS.

It is a requirement of bitstream conformance that, when there is one ormore values of i in the range of 0 to sps_num_subpics_minus1, inclusive,for which sps_subpic_treated_as_pic_flag[i] is equal to 1 andsps_subpic_width_minus1[i] plus 1 is not equal to(sps_pic_width_max_in_luma_samples+CtbSizeY−1)>>CtbLog2SizeY), the valueof sps_ref_wraparound_enabled_flag shall be equal to 0.

sps_temporal_mvp_enabled_flag equal to 1 specifies that temporal motionvector predictors are enabled and may be used in decoding of pictures inthe CLVS. sps_temporal_mvp_enabled_flag equal to 0 specifies thattemporal motion vector predictors are disabled and not used in decodingof pictures in the CLVS.

sps_sbtmvp_enabled_flag equal to 1 specifies that subblock-basedtemporal motion vector predictors are enabled and may be used indecoding of pictures with all slices having sh_slice_type not equal to Iin the CLVS. sps_sbtmvp_enabled_flag equal to 0 specifies thatsubblock-based temporal motion vector predictors are disabled and notused in decoding of pictures in the CLVS. When sps_sbtmvp_enabled_flagis not present, it is inferred to be equal to 0.

sps_amvr_enabled_flag equal to 1 specifies that adaptive motion vectordifference resolution is enabled and may be used in motion vector codingin decoding of pictures in the CVLS. amvr_enabled_flag equal to 0specifies that adaptive motion vector difference resolution is disabledand not used in motion vector coding in decoding of pictures in theCLVS.

sps_bdof_enabled_flag equal to 0 specifies that the bi-directionaloptical flow inter prediction is disabled and not used in decoding ofpictures in the CLVS. sps_bdof_enabled_flag equal to 1 specifies thatthe bi-directional optical flow inter prediction is enabled and may beused in decoding of pictures in the CLVS.

sps_bdof_control_present_in_ph_flag equal to 1 specifies thatph_bdof_disabled_flag is present in PHs referring to the SPS.sps_bdof_control_present_in_ph_flag equal to 0 specifies thatph_bdof_disabled_flag is not present in PHs referring to the SPS. Whensps_bdof_control_present_in_ph_flag is not present, the value ofsps_bdof_control_present_in_ph_flag is inferred to be equal to 0.

sps_smvd_enabled_flag equal to 1 specifies that symmetric motion vectordifference is enabled may be used in motion vector decoding in decodingof pictures in the CLVS. sps_smvd_enabled_flag equal to 0 specifies thatsymmetric motion vector difference is disabled and not used in motionvector coding in decoding of pictures in the CLVS.

sps_dmvr_enabled_flag equal to 1 specifies that decoder motion vectorrefinement based inter bi-prediction is enabled and may be used indecoding of pictures in the CLVS. sps_dmvr_enabled_flag equal to 0specifies that decoder motion vector refinement based interbi-prediction is disabled and not used in decoding of pictures in theCLVS.

sps_dmvr_control_present_in_ph_flag equal to 1 specifies thatph_dmvr_disabled_flag is present in PHs referring to the SPS.sps_dmvr_control_present_in_ph_flag equal to 0 specifies thatph_dmvr_disabled_flag is not present in PHs referring to the SPS. Whensps_dmvr_control_present_in_ph_flag is not present, the value ofsps_dmvr_control_present_in_ph_flag is inferred to be equal to 0.

sps_mmvd_enabled_flag equal to 1 specifies that merge mode with motionvector difference is enabled and may be used in decoding of pictures inthe CLVS. sps_mmvd_enabled_flag equal to 0 specifies that merge modewith motion vector difference is disabled and not used in in decoding ofpictures in the CLVS.

sps_six_minus_max_num_merge_cand specifies the maximum number of mergingmotion vector prediction (MVP) candidates supported in the SPSsubtracted from 6. The value of sps_six_minus_max_num_merge_cand shallbe in the range of 0 to 5, inclusive.

The maximum number of merging MVP candidates, MaxNumMergeCand, isderived as follows:MaxNumMergeCand=6−sps_six_minus_max_num_merge_candsps_sbt_enabled_flag equal to 0 specifies that subblock transform forinter-predicted CUs is disabled and not used in decoding of pictures inthe CLVS. sps_sbt_enabled_flag equal to 1 specifies that subblocktransform for inter-predicted CU is enabled and may be used in decodingof pictures in the CLVS.

sps_affine_enabled_flag equal to 0 specifies that affine model basedmotion compensation is disabled and not used in decoding of pictures inthe CLVS and inter_affine_flag and cu_affine_type_flag are not presentin the coding unit syntax of the CLVS. sps_affine_enabled_flag equal to1 specifies that affine model based motion compensation is enabled andmay be used in decoding of pictures in the CLVS and inter_affine_flagand cu_affine_type_flag may be present in the coding unit syntax of theCLVS.

sps_five_minus_max_num_subblock_merge_cand specifies the maximum numberof subblock-based merging motion vector prediction candidates supportedin the SPS subtracted from 5. The value ofsps_five_minus_max_num_subblock_merge_cand shall be in the range of 0 to5−sps_sbtmvp_enabled_flag, inclusive.

sps_affine_type_flag specifies whether 6-parameter affine model basedmotion compensation can be used for inter prediction. Ifsps_affine_type_flag is equal to 0, the syntax shall be constrained suchthat no 6-parameter affine model based motion compensation is used inthe CLVS, and cu_affine_type_flag is not present in coding unit syntaxin the CLVS. Otherwise (sps_affine_type_flag is equal to 1), 6-parameteraffine model based motion compensation can be used in the CLVS. When notpresent, the value of sps_affine_type_flag is inferred to be equal to 0.

sps_affine_amvr_enabled_flag equal to 1 specifies that adaptive motionvector difference resolution is enabled and may be used in motion vectorcoding of affine inter mode in decoding of pictures in the CLVS.sps_affine_amvr_enabled_flag equal to 0 specifies that adaptive motionvector difference resolution is disabled and not used in motion vectorcoding of affine inter mode in decoding of pictures in the CLVS. Whennot present, the value of sps_affine_amvr_enabled_flag is inferred to beequal to 0.

sps_affine_prof_enabled_flag equal to 0 specifies that the affine motioncompensation refined with optical flow is disabled and not used indecoding of pictures in the CLVS. sps_affine_prof_enabled_flag equal to1 specifies that the affine motion compensation refined with opticalflow is enabled and may be used in decoding of pictures in the CLVS.When not present, the value of sps_affine_prof_enabled_flag is inferredto be equal to 0.

sps_prof_control_present_in_ph_flag equal to 1 specifies thatph_prof_disabled_flag is present in PHs referring to the SPS.sps_prof_control_present_in_ph_flag equal to 0 specifies thatph_prof_disabled_flag is not present in PHs referring to the SPS. Whensps_prof_control_present_in_ph_flag is not present, the value ofsps_prof_control_present_in_ph_flag is inferred to be equal to 0.

sps_bcw_enabled_flag equal to 0 specifies that bi-prediction with CUweights is disabled and not used in decoding of pictures in the CLVS andbcw_idx is not present in the coding unit syntax of the CLVS.sps_bcw_enabled_flag equal to 1 specifies that bi-prediction with CUweights is enabled and may be used in decoding of pictures in the CLVSand bcw_idx may be present in the coding unit syntax of the CLVS.

sps_ciip_enabled_flag specifies that ciip_flag may be present in thecoding unit syntax for inter coding units. sps_ciip_enabled_flag equalto 0 specifies that ciip_flag is not present in the coding unit syntaxfor inter coding units.

sps_mmvd_fullpel_only_flag equal to 1 specifies that merge mode withmotion vector difference uses integer sample precision.sps_mmvd_fullpel_only_flag equal to 0 specifies that merge mode withmotion vector difference may use fractional sample precision. When notpresent, the value of sps_mmvd_fullpel_only_flag is inferred to be equalto 0.

sps_gpm_enabled_flag equal to 0 specifies that geometric partition basedmotion compensation is disabled and not used in decoding of pictures inthe CLVS and merge_gpm_partition_idx, merge_gpm_idx0, and merge_gpm_idx1are not present in the coding unit syntax of the CLVS.sps_gpm_enabled_flag equal to 1 specifies that geometric partition basedmotion compensation is enabled and may be used in decoding of picturesin the CLVS and merge_gpm_partition_idx, merge_gpm_idx0, andmerge_gpm_idx1 may be present in the coding unit syntax of the CLVS.When not present, the value of sps_gpm_enabled_flag is inferred to beequal to 0.

sps_max_num_merge_cand_minus_max_num_gpm_cand specifies the maximumnumber of geometric partitioning merge mode candidates supported in theSPS subtracted from MaxNumMergeCand. The value ofsps_max_num_merge_cand_minus_max_num_gpm_cand shall be in the range of 0to MaxNumMergeCand−2, inclusive.

The maximum number of geometric partitioning merge mode candidates,MaxNumGpmMergeCand, is derived as follows:

if( sps_gpm_enabled_flag && MaxNumMergeCand >= 3 )  MaxNumGpmMergeCand =MaxNumMergeCand −   sps_max_num_merge_cand_minus_max_num_gpm_cand elseif( sps_gpm_enabled_flag && MaxNumMergeCand = = 2 )  MaxNumGpmMergeCand= 2 else  MaxNumGpmMergeCand = 0

sps_log2_parallel_merge_level_minus2 plus 2 specifies the value of thevariable Log2ParMrgLevel, which is used in the derivation process forspatial merging candidates as specified, the derivation process formotion vectors and reference indices in subblock merge mode asspecified, and to control the invocation of the updating process for thehistory-based motion vector predictor list. The value ofsps_log2_parallel_merge_level_minus2 shall be in the range of 0 toCtbLog2SizeY−2, inclusive. The variable Log2ParMrgLevel is derived asfollows:Log2ParMrgLevel=sps_log2_parallel_merge_level_minus2+2sps_isp_enabled_flag equal to 1 specifies that intra prediction withsubpartitions is enabled and may be used in decoding of pictures in theCLVS. sps_isp_enabled_flag equal to 0 specifies that intra predictionwith subpartitions is disabled and not used in decoding of pictures inthe CLVS.

sps_mrl_enabled_flag equal to 1 specifies that intra prediction withmultiple reference lines is enabled and may be used in decoding ofpictures in the CLVS. sps_mrl_enabled_flag equal to 0 specifies thatintra prediction with multiple reference lines is disabled and not usedin decoding of pictures in the CLVS.

sps_mip_enabled_flag equal to 1 specifies that matrix-based intraprediction is enabled and may be used in decoding of pictures in theCLVS. sps_mip_enabled_flag equal to 0 specifies that matrix-based intraprediction is disabled and not used in decoding of pictures in the CLVS.

sps_cclm_enabled_flag equal to 0 specifies that the cross-componentlinear model intra prediction from luma component to chroma component isdisabled and not used in decoding of pictures in the CLVS.sps_cclm_enabled_flag equal to 1 specifies that the cross-componentlinear model intra prediction from luma component to chroma component isenabled and may be used in decoding of pictures in the CLVS. Whensps_cclm_enabled_flag is not present, it is inferred to be equal to 0.

sps_chroma_horizontal_collocated_flag equal to 1 specifies thatprediction processes operate in a manner designed for chroma samplepositions that are not horizontally shifted relative to correspondingluma sample positions. sps_chroma_horizontal_collocated_flag equal to 0specifies that prediction processes operate in a manner designed forchroma sample positions that are shifted to the right by 0.5 in units ofluma samples relative to corresponding luma sample positions. Whensps_chroma_horizontal_collocated_flag is not present, it is inferred tobe equal to 1.

sps_chroma_vertical_collocated_flag equal to 1 specifies that predictionprocesses operate in a manner designed for chroma sample positions thatare not vertically shifted relative to corresponding luma samplepositions. sps_chroma_vertical_collocated_flag equal to 0 specifies thatprediction processes operate in a manner designed for chroma samplepositions that are shifted downward by 0.5 in units of luma samplesrelative to corresponding luma sample positions. Whensps_chroma_vertical_collocated_flag is not present, it is inferred to beequal to 1.

sps_mts_enabled_flag equal to 1 specifies thatsps_explicit_mts_intra_enabled_flag andsps_explicit_mts_inter_enabled_flag are present in the SPS.sps_mts_enabled_flag equal to 0 specifies thatsps_explicit_mts_intra_enabled_flag andsps_explicit_mts_inter_enabled_flag are not present in the SPS.

sps_explicit_mts_intra_enabled_flag equal to 1 specifies that mts_idxmay be present in the intra coding unit syntax of the CLVS.sps_explicit_mts_intra_enabled_flag equal to 0 specifies that mts_idx isnot present in the intra coding unit syntax of the CLVS. When notpresent, the value of sps_explicit_mts_intra_enabled_flag is inferred tobe equal to 0.

sps_explicit_mts_inter_enabled_flag equal to 1 specifies that mts_idxmay be present in the inter coding unit syntax of the CLVS.sps_explicit_mts_inter_enabled_flag equal to 0 specifies that mts_idx isnot present in the inter coding unit syntax of the CLVS. When notpresent, the value of sps_explicit_mts_inter_enabled_flag is inferred tobe equal to 0.

sps_palette_enabled_flag equal to 1 specifies that pred_mode_plt_flagmay be present in the coding unit syntax of the CLVS.sps_palette_enabled_flag equal to 0 specifies that pred_mode_plt_flag isnot present in the coding unit syntax of the CLVS. Whensps_palette_enabled_flag is not present, it is inferred to be equal to0.

sps_act_enabled_flag equal to 1 specifies that adaptive colour transformis enabled and may be used in decoding of pictures in the CLVS and thecu_act_enabled_flag may be present in the coding unit syntax of theCLVS. sps_act_enabled_flag equal to 0 specifies that adaptive colourtransform is disabled and not used in decoding of pictures in the CLVSand cu_act_enabled_flag is not present in the coding unit syntax of theCLVS. When sps_act_enabled_flag is not present, it is inferred to beequal to 0.

sps_internal_bit_depth_minus_input_bit_depth specifies the minimumallowed quantization parameter for transform skip mode as follows:QpPrimeTsMin=4+6*sps_internal_bit_depth_minus_input_bit_depth

The value of sps_internal_bit_depth_minus_input_bit_depth shall be inthe range of 0 to 8, inclusive.

sps_ibc_enabled_flag equal to 1 specifies that the IBC prediction modeis enabled and may be used in decoding of pictures in the CLVS.sps_ibc_enabled_flag equal to 0 specifies that the IBC prediction modeis disabled and not used in decoding of pictures in the CLVS. Whensps_ibc_enabled_flag is not present, it is inferred to be equal to 0.

sps_six_minus_max_num_ibc_merge_cand, when sps_ibc_enabled_flag is equalto 1, specifies the maximum number of IBC merging block vectorprediction (BVP) candidates supported in the SPS subtracted from 6. Thevalue of sps_six_minus_max_num_ibc_merge_cand shall be in the range of 0to 5, inclusive.

The maximum number of IBC merging BVP candidates, MaxNumIbcMergeCand, isderived as follows:

if( sps_ibc_enabled_flag )  MaxNumIbcMergeCand =  6 −sps_six_minus_max_num_ibc_merge_cand else  MaxNumIbcMergeCand = 0

sps_lmcs_enabled_flag equal to 1 specifies that luma mapping with chromascaling is enabled and may be used in decoding of pictures in the CLVS.sps_lmcs_enabled_flag equal to 0 specifies that luma mapping with chromascaling is disabled and not used in decoding of pictures in the CLVS.

sps_lfnst_enabled_flag equal to 1 specifies that lfnst_idx may bepresent in intra coding unit syntax. sps_lfnst_enabled_flag equal to 0specifies that lfnst_idx is not present in intra coding unit syntax.

sps_ladf_enabled_flag equal to 1 specifies thatsps_num_ladf_intervals_minus2, sps_ladf_lowest_interval_qp_offset,sps_ladf_qp_offset[i], and sps_ladf_delta_threshold_minus1[i] arepresent in the SPS. sps_ladf_enabled_flag equal to 0 specifies thatsps_num_ladf_intervals_minus2, sps_ladf_lowest_interval_qp_offset,sps_ladf_qp_offset[i], and sps_ladf_delta_threshold_minus1[i] are notpresent in the SPS.

sps_num_ladf_intervals_minus2 plus 2 specifies the number ofsps_ladf_delta_threshold_minus1[i] and sps_ladf_qp_offset[i] syntaxelements that are present in the SPS. The value ofsps_num_ladf_intervals_minus2 shall be in the range of 0 to 3,inclusive.

sps_ladf_lowest_interval_qp_offset specifies the offset used to derivethe variable qP as specified. The value ofsps_ladf_lowest_interval_qp_offset shall be in the range of −63 to 63,inclusive.

sps_ladf_qp_offset[i] specifies the offset array used to derive thevariable qP as specified. The value of sps_ladf_qp_offset[i] shall be inthe range of −63 to 63, inclusive.

sps_ladf_delta_threshold_minus1[i] is used to compute the values ofSpsLadfIntervalLowerBound[i], which specifies the lower bound of thei-th luma intensity level interval. The value ofsps_ladf_delta_threshold_minus1 [i] shall be in the range of 0 to2^(BitDepth)−3, inclusive.

The value of SpsLadfIntervalLowerBound[0] is set equal to 0.

For each value of i in the range of 0 to sps_num_ladf_intervals_minus2,inclusive, the variable SpsLadfIntervalLowerBound[i+1] is derived asfollows:

$\begin{matrix}{{SpsLadfIntervalLowerBoun{d\left\lbrack {i + 1} \right\rbrack}} = {{SpsLadfIntervalLowerBoun{d\lbrack i\rbrack}} + {{sps\_ ladf}{\_ delta}{\_ threshold}{{\_ minus1}\lbrack i\rbrack}} + 1}} & \;\end{matrix}$

sps_explicit_scaling_list_enabled_flag equal to 1 specifies that the useof an explicit scaling list, which is signalled in a scaling list APS,in the scaling process for transform coefficients when decoding a sliceis enabled for the CLVS. sps_explicit_scaling_list_enabled_flag equal to0 specifies that the use of an explicit scaling list in the scalingprocess for transform coefficients when decoding a slice is disabled forthe CLVS.

sps_scaling_matrix_for_lfnst_disabled_flag equal to 1 specifies thatscaling matrices are disabled and not applied to blocks coded with LFNSTfor the CLVS. sps_scaling_matrix_for_lfnst_disabled_flag equal to 0specifies that the scaling matrices is enabled and may be applied toblocks coded with LFNST for the CLVS. When not present, the value ofsps_scaling_matrix_for_lfnst_disabled_flag is inferred to be equal to 1.

sps_scaling_matrix_for_alternative_colour_space_disabled_flag equal to 1specifies that for the CLVS scaling matrices are disabled and notapplied to blocks when the colour space of the blocks is not equal tothe designated colour space of scaling matrix.sps_scaling_matrix_for_alternative_colour_space_disabled_flag equal to 0specifies that for the CLVS scaling matrices are enabled and may beapplied to the blocks when the colour space of the blocks is equal tothe designated colour space of scaling matrices. When not present, thevalue of sps_scaling_matrix_for_alternative_colour_sapce_disabled_flagis inferred to be equal to 0.

sps_scaling_matrix_designated_colour_space_flag equal to 1 specifiesthat the designated colour space of scaling matrices is the originalcolour space. sps_scaling_matrix_designated_colour_space_flag equal to 0specifies that the designated colour space of scaling matrices is thetransformed colour space. When not present, the value ofsps_scaling_matrix_designated_colour_space_flag is inferred to be equalto 1.

sps_dep_quant_enabled_flag equal to 0 specifies that dependentquantization is disabled and not used for pictures referring to the SPS.sps_dep_quant_enabled_flag equal to 1 specifies that dependentquantization is enabled and may be used for pictures referring to theSPS.

sps_sign_data_hiding_enabled_flag equal to 0 specifies that sign bithiding is disabled and not used for pictures referring to the SPS.sps_sign_data_hiding_enabled_flag equal to 1 specifies that sign bithiding is enabled and may be used for pictures referring to the SPS.When sps_sign_data_hiding_enabled_flag is not present, it is inferred tobe equal to 0.

sps_virtual_boundaries_enabled_flag equal to 1 specifies that disablingin-loop filtering across virtual boundaries is enabled and may beapplied in the coded pictures in the CLVS.sps_virtual_boundaries_enabled_flag equal to 0 specifies that disablingin-loop filtering across virtual boundaries is disabled and not appliedin the coded pictures in the CLVS. In-loop filtering operations includethe deblocking filter, sample adaptive offset filter, and adaptive loopfilter operations.

sps_virtual_boundaries_present_flag equal to 1 specifies thatinformation of virtual boundaries is signalled in the SPS.sps_virtual_boundaries_present_flag equal to 0 specifies thatinformation of virtual boundaries is not signalled in the SPS. Whenthere is one or more than one virtual boundaries signalled in the SPS,the in-loop filtering operations are disabled across the virtualboundaries in pictures referring to the SPS. In-loop filteringoperations include the deblocking filter, sample adaptive offset filter,and adaptive loop filter operations.

It is a requirement of bitstream conformance that when the value ofsps_res_change_in_clvs_allowed_flag is equal to 1, the value ofsps_virtual_boundaries_present_flag shall be equal to 0.

sps_num_ver_virtual_boundaries specifies the number ofsps_virtual_boundary_pos_x[i] syntax elements that are present in theSPS. When sps_num_ver_virtual_boundaries is not present, it is inferredto be equal to 0.

sps_virtual_boundary_pos_x[i] specifies the location of the i-thvertical virtual boundary in units of luma samples divided by 8. Thevalue of sps_virtual_boundary_pos_x[i] shall be in the range of 1 toCeil(sps_pic_width_max_in_luma_samples÷8)−1, inclusive.

sps_num_hor_virtual_boundaries specifies the number ofsps_virtual_boundary_pos_y[i] syntax elements that are present in theSPS. When sps_num_hor_virtual_boundaries is not present, it is inferredto be equal to 0.

When sps_virtual_boundaries_enabled_flag is equal to 1 andsps_virtual_boundaries_present_flag is equal to 1, the sum ofsps_num_ver_virtual_boundaries and sps_num_hor_virtual_boundaries shallbe greater than 0.

sps_virtual_boundary_pos_y[i] specifies the location of the i-thhorizontal virtual boundary in units of luma samples divided by 8. Thevalue of sps_virtual_boundary_pos_y[i] shall be in the range of 1 toCeil(sps_pic_height_max_in_luma_samples÷8)−1, inclusive.

sps_general_hrd_params_present_flag equal to 1 specifies that the SPScontains a general_hrd_parameters( ) syntax structure and anols_hrd_parameters( ) syntax structure.sps_general_hrd_params_present_flag equal to 0 specifies that the SPSdoes not contain a general_hrd_parameters( ) syntax structure or anols_hrd_parameters( ) syntax structure.

sps_sublayer_cpb_params_present_flag equal to 1 specifies that theols_hrd_parameters( ) syntax structure in the SPS includes HRDparameters for sublayer representations with TemporalId in the range of0 to sps_max_sublayers_minus1, inclusive.sps_sublayer_cpb_params_present_flag equal to 0 specifies that theols_hrd_parameters( ) syntax structure in the SPS includes HRDparameters for the sublayer representation with TemporalId equal tosps_max_sublayers_minus1 only. When sps_max_sublayers_minus1 is equal to0, the value of sps_sublayer_cpb_params_present_flag is inferred to beequal to 0.

When sps_sublayer_cpb_params_present_flag is equal to 0, the HRDparameters for the sublayer representations with TemporalId in the rangeof 0 to sps_max_sublayers_minus1−1, inclusive, are inferred to be thesame as that for the sublayer representation with TemporalId equal tosps_max_sublayers_minus1. These include the HRD parameters starting fromthe fixed_pic_rate_general_flag[i] syntax element till thesublayer_hrd_parameters(i) syntax structure immediately under thecondition “if(general_vcl_hrd_params_present_flag)” in theols_hrd_parameters syntax structure.

sps_field_seq_flag equal to 1 indicates that the CLVS conveys picturesthat represent fields. sps_field_seq_flag equal to 0 indicates that theCLVS conveys pictures that represent frames. Whengeneral_frame_only_constraint_flag is equal to 1, the value ofsps_field_seq_flag shall be equal to 0.

When sps_field_seq_flag is equal to 1, a frame-field information SEImessage shall be present for every coded picture in the CLVS.

-   -   NOTE—The specified decoding process does not treat pictures that        represent fields or frames differently. A sequence of pictures        that represent fields would therefore be coded with the picture        dimensions of an individual field. For example, pictures that        represent 1080i fields would commonly have cropped output        dimensions of 1920×540, while the sequence picture rate would        commonly express the rate of the source fields (typically        between 50 and 60 Hz), instead of the source frame rate        (typically between 25 and 30 Hz).

sps_vui_parameters_present_flag equal to 1 specifies that the syntaxstructure vui_parameters( ) is present in the SPS RBSP syntax structure.sps_vui_parameters_present_flag equal to 0 specifies that the syntaxstructure vui_parameters( ) is not present in the SPS RBSP syntaxstructure.

sps_extension_flag equal to 0 specifies that no sps_extension_data_flagsyntax elements are present in the SPS RBSP syntax structure.sps_extension_flag equal to 1 specifies that there aresps_extension_data_flag syntax elements present in the SPS RBSP syntaxstructure.

sps_extension_data_flag may have any value. Its presence and value donot affect decoder conformance to profiles specified in this version ofthis Specification. Decoders conforming to this version of thisSpecification shall ignore all sps_extension_data_flag syntax elements.

As provided in Table 2, a NAL unit may include a pic_parameter_set_rbsp(PPS) syntax structure. Table 4 illustrates the syntax structure of thedecoding capability information provided in JVET-R2001.

TABLE 4 pic_parameter_set_rbsp( ) { Descriptor  pps_pic_parameter_set_idu(6)  pps_seq_parameter_set_id u(4)  pps_mixed_nalu_types_in_pic_flagu(1)  pps_pic_width_in_luma_samples ue(v) pps_pic_height_in_luma_samples ue(v)  pps_conformance_window_flag u(1) if( pps_conformance_window_flag ) {   pps_conf_win_left_offset ue(v)  pps_conf_win_right_offset ue(v)   pps_conf_win_top_offset ue(v)  pps_conf_win_bottom_offset ue(v)  } pps_scaling_window_explicit_signalling_flag u(1)  if(pps_scaling_window_explicit_signalling_flag ) {  pps_scaling_win_left_offset se(v)   pps_scaling_win_right_offset se(v)  pps_scaling_win_top_offset se(v)   pps_scaling_win_bottom_offset se(v) }  pps_output_flag_present_flag u(1)  pps_no_pic_partition_flag u(1) pps_subpic_id_mapping_present_flag u(1)  if(pps_subpic_id_mapping_present_flag ) {   if( !pps_no_pic_partition_flag)    pps_num_subpics_minus1 ue(v)   pps_subpic_id_len_minus1 ue(v)  for( i = 0; i <= pps_num_subpic_minus1; i++ )    pps_subpic_id[ i ]u(v)  }  if( !pps_no_pic_partition_flag ) {   pps_log2_ctu_size_minus5u(2)   pps_num_exp_tile_columns_minus1 ue(v)  pps_num_exp_tile_rows_minus1 ue(v)   for( i = 0; i <=pps_num_exp_tile_columns_minus1; i++ )    pps_tile_column_width_minus1[i ] ue(v)   for( i = 0; i <= pps_num_exp_tile_rows_minus1; i++ )   pps_tile_row_height_minus1[ i ] ue(v)   if( NumTilesInPic > 1 ) {   pps_loop_filter_across_tiles_enabled_flag u(1)    pps_rect_slice_flagu(1)   }   if( pps_rect_slice_flag )    pps_single_slice_per_subpic_flagu(1)   if( pps_rect_slice_flag && !pps_single_slice_per_subpic_flag ) {   pps_num_slices_in_pic_minus1 ue(v)    if(pps_num_slices_in_pic_minus1 > 1 )     pps_tile_idx_delta_present_flagu(1)   for( i = 0; i < pps_num_slices_in_pic_minus1; i++ ) {    if(SliceTopLeftTileIdx[ i ] % NumTileColumns != NumTileColumns − 1 )    pps_slice_width_in_tiles_minus1[ i ] ue(v)    if(SliceTopLeftTileIdx[ i ] / NumTileColumns != NumTileRows − 1 &&      (pps_tile_idx_delta_present_flag | |      SliceTopLeftTileIdx[ i ] %NumTileColumns = = 0 ) )     pps_slice_height_in_tiles_minus1[ i ] ue(v)   if( pps_slice_width_in_tiles_minus1[ i ] = = 0 &&      pps_slice_height_in_tiles_minus1[ i ] = = 0 &&       RowHeight[SliceTopLeftTileIdx[ i ] / NumTileColumns ] > 1 ) {     pps_num_exp_slices_in_tile[i] ue(v)      for( j = 0; j <pps_num_exp_slices_in_tile[ i ]; j++ )      pps_exp_slice_height_in_ctus_minus1[ i ][ j ] ue(v)      i +=NumSlicesInTile[ i ] − 1     }     if( pps_tile_idx_delta_present_flag&& i < pps_num_slices_in_pic_minus1 )      pps_tile_idx_delta_val[ i ]se(v)    }   }   if( !pps_rect_slice_flag | |pps_single_slice_per_subpic_flag | |    pps_num_slices_in_pic_minus1 > 0)  pps_loop_filter_across_slices_enabled_flag u(1)  }   pps_cabac_init_present_flag u(1)  for( i = 0; i < 2; i++ )  pps_num_ref_idx_default_active_minus1[ i ] ue(v) pps_rpl1_idx_present_flag u(1)  pps_init_qp_minus26 se(v) pps_cu_qp_delta_enabled_flag u(1)  pps_chroma_tool_offsets_present_flagu(1)  if( pps_chroma_tool_offsets_present_flag ) {   pps_cb_qp_offsetse(v)   pps_cr_qp_offset se(v)   pps_joint_cbcr_qp_offset_present_flagu(1)   if( pps_joint_cbcr_qp_offset_present_flag )   pps_joint_cbcr_qp_offset_value se(v)  pps_slice_chroma_qp_offsets_present_flag u(1)  pps_cu_chroma_qp_offset_list_enabled_flag u(1)  }  if(pps_cu_chroma_qp_offset_list_enabled_flag ) {  pps_chroma_qp_offset_list_len_minus1 ue(v)   for( i = 0; i <=pps_chroma_qp_offset_list_len_minus1; i++ ) {    pps_cb_qp_offset_list[i ] se(v)    pps_cr_qp_offset_list[ i ] se(v)    if(pps_joint_cbcr_qp_offset_present_flag )    pps_joint_cbcr_qp_offset_list[ i ] se(v)   }  } pps_weighted_pred_flag u(1)  pps_weighted_bipred_flag u(1) pps_deblocking_filter_control_present_flag u(1)  if(pps_deblocking_filter_control_present_flag ) {  pps_deblocking_filter_override_enabled_flag u(1)  pps_deblocking_filter_disabled_flag u(1)   if(!pps_no_pic_partition_flag &&pps_deblocking_filter_override_enabled_flag )    pps_dbf_info_in_ph_flagu(1)   if( !pps_deblocking_filter_disabled_flag ) {   pps_luma_beta_offset_div2 se(v)    pps_luma_tc_offset_div2 se(v)   if( pps_chroma_tool_offsets_present_flag ) {    pps_cb_beta_offset_div2 se(v)     pps_cb_tc_offset_div2 se(v)    pps_cr_beta_offset_div2 se(v)     pps_cr_tc_offset_div2 se(v)    }  }  }  if( !pps_no_pic_partition_flag ) {   pps_rpl_info_in_ph_flagu(1)   pps_sao_info_in_ph_flag u(1)   pps_alf_info_in_ph_flag u(1)   if(( pps_weighted_pred_flag | | pps_weighted_bipred_flag ) &&    pps_rpl_info_in_ph_flag )    pps_wp_info_in_ph_flag u(1)  pps_qp_delta_info_in_ph_flag u(1)  }  pps_ref_wraparound_enabled_flagu(1)  if( pps_ref_wraparound_enabled_flag )  pps_pic_width_minus_wraparound_offset ue(v) pps_picture_header_extension_present_flag u(1) pps_slice_header_extension_present_flag u(1)  pps_extension_flag u(1) if( pps_extension_flag )   while( more_rbsp_data( ) )   pps_extension_data_flag u(1)  rbsp_trailing_bits( ) }

With respect to Table 4, JVET-R2001 provides the following semantics:

A PPS RBSP shall be available to the decoding process prior to it beingreferenced, included in at least one AU with TemporalId less than orequal to the TemporalId of the PPS NAL unit or provided through externalmeans.

All PPS NAL units with a particular value of pps_pic_parameter_set_idwithin a PU shall have the same content.

pps_pic_parameter_set_id identifies the PPS for reference by othersyntax elements.

PPS NAL units, regardless of the nuh_layer_id values, share the samevalue space of pps_pic_parameter_set_id.

Let ppsLayerId be the value of the nuh_layer_id of a particular PPS NALunit, and vclLayerId be the value of the nuh_layer_id of a particularVCL NAL unit. The particular VCL NAL unit shall not refer to theparticular PPS NAL unit unless ppsLayerId is less than or equal tovclLayerId and all OLSs specified by the VPS that contain the layer withnuh_layer_id equal to vclLayerId also contain the layer withnuh_layer_id equal to ppslayerId.

pps_seq_parameter_set_id specifies the value of sps_seq_parameter_set_idfor the SPS. The value of pps_seq_parameter_set_id shall be in the rangeof 0 to 15, inclusive. The value of pps_seq_parameter_set_id shall bethe same in all PPSs that are referred to by coded pictures in a CLVS.

pps_mixed_nalu_types_in_pic_flag equal to 1 specifies that each picturereferring to the PPS has more than one VCL NAL unit and the VCL NALunits do not have the same value of nal_unit_type.pps_mixed_nalu_types_in_pic_flag equal to 0 specifies that each picturereferring to the PPS has one or more VCL NAL units and the VCL NAL unitsof each picture referring to the PPS have the same value ofnal_unit_type.

When no_mixed_nalu_types_in_pic_constraint_flag is equal to 1, the valueof pps_mixed_nalu_types_in_pic_flag shall be equal to 0.

NOTE—pps_mixed_nalu_types_in_pic_flag equal to 1 indicates that picturesreferring to the PPS contain slices with different NAL unit types, e.g.,coded pictures originating from a subpicture bitstream merging operationfor which encoders have to ensure matching bitstream structure andfurther alignment of parameters of the original bitstreams. One exampleof such alignments is as follows: When the value ofsps_idr_rpl_present_flag is equal to 0 andpps_mixed_nalu_types_in_pic_flag is equal to 1, a picture referring tothe PPS cannot have slices with nal_unit_type equal to IDR_W_RADL orIDR_N_LP.

pps_pic_width_in_luma_samples specifies the width of each decodedpicture referring to the PPS in units of luma samples.pps_pic_width_in_luma_samples shall not be equal to 0, shall be aninteger multiple of Max(8, MinCbSizeY), and shall be less than or equalto sps_pic_width_max_in_luma_samples.

When sps_res_change_in_clvs_allowed_flag equal to 0, the value ofpps_pic_width_in_luma_samples shall be equal tosps_pic_width_max_in_luma_samples.

When sps_ref_wraparound_enabled_flag is equal to 1, the value of(CtbSizeY/MinCbSizeY+1) shall be less than or equal to the value of(pps_pic_width_in_luma_samples/MinCbSizeY−1).

pps_pic_height_in_luma_samples specifies the height of each decodedpicture referring to the PPS in units of luma samples.pps_pic_height_in_luma_samples shall not be equal to 0 and shall be aninteger multiple of Max(8, MinCbSizeY), and shall be less than or equalto sps_pic_height_max_in_luma_samples.

When sps_res_change_in_clvs_allowed_flag equal to 0, the value ofpps_pic_height_in_luma_samples shall be equal tosps_pic_height_max_in_luma_samples.

The variables PicWidthInCtbsY, PicHeightInCtbsY, PicSizeInCtbsY,PicWidthInMinCbsY, PicHeightInMinCbsY, PicSizeInMinCbsY,PicSizeInSamplesY, PicWidthInSamplesC and PicHeightInSamplesC arederived as follows:PicWidthInCtbsY=Ceil(pps_pic_width_in_luma_samples÷CtbSizeY)PicHeightInCtbsY=Ceil(pps_pic_height_in_luma_samples÷CtbSizeY)PicSizeInCtbsY=PicWidthInCtbsY*PicHeightInCtbsYPicWidthInMinCbsY=pps_pic_width_in_luma_samples/MinCbSizeYPicHeightInMinCbsY=pps_pic_height_in_luma_samples/MinCbSizeYPicSizeInMinCbsY=PicWidthInMinCbsY*PicHeightInMinCbsYPicSizeInSamplesY=pps_pic_width_in_luma_samples*pps_pic_height_in_luma_samplesPicWidthInSamplesC=pps_pic_width_in_luma_samples/SubWidthCPicHeightInSamplesC=pps_pic_height_in_luma_samples/SubHeightC

pps_conformance_window_flag equal to 1 specifies that the conformancecropping window offset parameters follow next in the PPS.pps_conformance_window_flag equal to 0 specifies that the conformancecropping window offset parameters are not present in the PPS.

When pps_pic_width_in_luma_samples is equal tosps_pic_width_max_in_luma_samples and pps_pic_height_in_luma_samples isequal to sps_pic_height_max_in_luma_samples, the value ofpps_conformance_window_flag shall be equal to 0.

pps_conf_win_left_offset, pps_conf_win_right_offset,pps_conf_win_top_offset, and pps_conf_win_bottom_offset specify thesamples of the pictures in the CLVS that are output from the decodingprocess, in terms of a rectangular region specified in picturecoordinates for output.

When pps_conformance_window_flag is equal to 0, the following applies:

-   -   If pps_pic_width_in_luma_samples is equal to        sps_pic_width_max_in_luma_samples and        pps_pic_height_in_luma_samples is equal to        sps_pic_height_max_in_luma_samples, the values of        pps_conf_win_left_offset, pps_conf_win_right_offset,        pps_conf_win_top_offset, and pps_conf_win_bottom_offset are        inferred to be equal to sps_conf_win_left_offset,        sps_conf_win_right_offset, sps_conf_win_top_offset, and        sps_conf_win_bottom_offset, respectively.    -   Otherwise, the values of pps_conf_win_left_offset,        pps_conf_win_right_offset, pps_conf_win_top_offset, and        pps_conf_win_bottom_offset are inferred to be equal to 0.

The conformance cropping window contains the luma samples withhorizontal picture coordinates from SubWidthC*pps_conf_win_left_offsetto pps_pic_width_in_luma_samples−(SubWidthC*pps_conf_win_right_offset+1)and vertical picture coordinates from SubHeightC*pps_conf_win_top_offsettopps_pic_height_in_luma_samples−(SubHeightC*pps_conf_win_bottom_offset+1),inclusive.

The value ofSubWidthC*(pps_conf_win_left_offset+pps_conf_win_right_offset) shall beless than pps_pic_width_in_luma_samples, and the value ofSubHeightC*(pps_conf_win_top_offset+pps_conf_win_bottom_offset) shall beless than pps_pic_height_in_luma_samples.

When ChromaArrayType is not equal to 0, the corresponding specifiedsamples of the two chroma arrays are the samples having picturecoordinates (x/SubWidthC, y/SubHeightC), where (x, y) are the picturecoordinates of the specified luma samples.

NOTE—The conformance cropping window offset parameters are only appliedat the output. All internal decoding processes are applied to theuncropped picture size.

Let ppsA and ppsB be any two PPSs referring to the same SPS. It is arequirement of bitstream conformance that, when ppsA and ppsB have thesame the values of pps_pic_width_in_luma_samples andpps_pic_height_in_luma_samples, respectively, ppsA and ppsB shall havethe same values of pps_conf_win_left_offset, pps_conf_win_right_offset,pps_conf_win_top_offset, and pps_conf_win_bottom_offset, respectively.

When pps_pic_width_in_luma_samples is equal tosps_pic_width_max_in_luma_samples and pps_pic_height_in_luma_samples isequal to sps_pic_height_max_in_luma_samples, it is a requirement ofbitstream conformance that pps_conf_win_left_offset,pps_conf_win_right_offset, pps_conf_win_top_offset, andpps_conf_win_bottom_offset, are equal to sps_conf_win_left_offset,sps_conf_win_right_offset, sps_conf_win_top_offset, andsps_conf_win_bottom_offset, respectively.

pps_scaling_window_explicit_signalling_flag equal to 1 specifies thatthe scaling window offset parameters are present in the PPS.pps_scaling_window_explicit_signalling_flag equal to 0 specifies thatthe scaling window offset parameters are not present in the PPS. Whensps_ref_pic_resampling_enabled_flag is equal to 0, the value ofpps_scaling_window_explicit_signalling_flag shall be equal to 0.

pps_scaling_win_left_offset, pps_scaling_win_right_offset,pps_scaling_win_top_offset, and pps_scaling_win_bottom_offset specifythe offsets that are applied to the picture size for scaling ratiocalculation. When not present, the values ofpps_scaling_win_left_offset, pps_scaling_win_right_offset,pps_scaling_win_top_offset, and pps_scaling_win_bottom_offset areinferred to be equal to pps_conf_win_left_offset,pps_conf_win_right_offset, pps_conf_win_top_offset, andpps_conf_win_bottom_offset, respectively.

The value ofSubWidthC*(Abs(pps_scaling_win_left_offset)+Abs(pps_scaling_win_right_offset))shall be less than pps_pic_width_in_luma_samples, and the value ofSubHeightC*(Abs(pps_scaling_win_top_offset)+Abs(pps_scaling_win_bottom_offset))shall be less than pps_pic_height_in_luma_samples.

The variables CurrPicScalWinWidthL and CurrPicScalWinHeightL are derivedas follows:CurrPicScalWinWidthL=pps_pic_width_in_luma_samples−SubWidthC*(pps_scaling_win_right_offset+pps_scaling_win_left_offset)CurrPicScalWinHeightL=pps_pic_height_in_luma_samples−SubHeightC*(pps_scaling_win_bottom_offset+pps_scaling_win_top_offset)

Let refPicScalWinWidthL and refPicScalWinHeightL be theCurrPicScalWinWidthL and CurrPicScalWinHeightL, respectively, of areference picture of a current picture referring to this PPS. It is arequirement of bitstream conformance that all of the followingconditions shall be satisfied:

-   -   CurrPicScalWinWidthL*2 is greater than or equal to        refPicScalWinWidthL.    -   CurrPicScalWinHeightL*2 is greater than or equal to        refPicScalWinHeightL.    -   CurrPicScalWinWidthL is less than or equal to        refPicScalWinWidthL*8.    -   CurrPicScalWinHeightL is less than or equal to        refPicScalWinHeightL*8.    -   CurrPicScalWinWidthL*sps_pic_width_max_in_luma_samples is        greater than or equal to        refPicScalWinWidthL*(pps_pic_width_in_luma_samples−Max(8,        MinCbSizeY)).    -   CurrPicScalWinHeightL*sps_pic_height_max_in_luma_samples is        greater than or equal to        refPicScalWinHeightL*(pps_pic_height_in_luma_samples−Max(8,        MinCbSizeY)).

pps_output_flag_present_flag equal to 1 specifies that theph_pic_output_flag syntax element is present in PHs referring to thePPS. pps_output_flag_present_flag equal to 0 specifies that theph_pic_output_flag syntax element is not present in PHs referring to thePPS.

pps_no_pic_partition_flag equal to 1 specifies that no picturepartitioning is applied to each picture referring to the PPS.pps_no_pic_partition_flag equal to 0 specifies that each picturereferring to the PPS may be partitioned into more than one tile orslice.

It is a requirement of bitstream conformance that the value ofpps_no_pic_partition_flag shall be the same for all PPSs that arereferred to by coded pictures within a CLVS.

When sps_num_subpics_minus1 is greater than 0 orpps_mixed_nalu_types_in_pic_flag is equal to 1, the value ofpps_no_pic_partition_flag shall be equal to 0.

pps_subpic_id_mapping_present_flag equal to 1 specifies that thesubpicture ID mapping is signalled in the PPS.pps_subpic_id_mapping_present_flag equal to 0 specifies that thesubpicture ID mapping is not signalled in the PPS. Ifsps_subpic_id_mapping_explicitly_signalled_flag is 0 orsps_subpic_id_mapping_present_flag is equal to 1, the value ofpps_subpic_id_mapping_present_flag shall be equal to 0. Otherwise(sps_subpic_id_mapping_explicitly_signalled_flag is equal to 1 andsps_subpic_id_mapping_present_flag is equal to 0), the value ofpps_subpic_id_mapping_present_flag shall be equal to 1.

pps_num_subpics_minus1 shall be equal to sps_num_subpics_minus1. Whenno_pic_partition_flag is equal to 1, the value of pps_num_subpics_minus1is inferred to be equal to 0.

pps_subpic_id_len_minus1 shall be equal to sps_subpic_id_len_minus1.

pps_subpic_id[i] specifies the subpicture ID of the i-th subpicture. Thelength of the pps_subpic_id[i] syntax element ispps_subpic_id_len_minus1+1 bits.

The variable SubpicIdVal[i], for each value of i in the range of 0 tosps_num_subpics_minus1, inclusive, is derived as follows:

for( i = 0; i <= sps_num_subpics_minus1; i++ )  if(sps_subpic_id_mapping_explicitly_signalled_flag )   SubpicIdVal[ i ] =pps_subpic_id_mapping_present_flag ? pps_subpic_id[ i ] : sps_subpic_id[i ]  else   SubpicIdVal[ i ] = i

It is a requirement of bitstream conformance that both of the followingconstraints apply:

-   -   For any two different values of i and j in the range of 0 to        sps_num_subpics_minus1, inclusive, SubpicIdVal[i] shall not be        equal to SubpicIdVal[j].    -   For each value of i in the range of 0 to sps_num_subpics_minus1,        inclusive, when the value of SubpicIdVal[i] of a current        picture, with nuh_layer_id equal to a particular value layerId,        is not equal to the value of SubpicIdVal[i] of a reference        picture that has nuh_layer_id equal to layerId, the active        entries of the RPLs of the coded slices in the i-th subpicture        of the current picture shall not include that reference picture.

pps_log2_ctu_size_minus5 plus 5 specifies the luma coding tree blocksize of each CTU. pps_log2_ctu_size_minus5 shall be equal tosps_log2_ctu_size_minus5.

pps_num_exp_tile_columns_minus1 plus 1 specifies the number ofexplicitly provided tile column widths. The value ofpps_num_exp_tile_columns_minus1 shall be in the range of 0 toPicWidthInCtbsY−1, inclusive. When pps_no_pic_partition_flag is equal to1, the value of pps_num_exp_tile_columns_minus1 is inferred to be equalto 0.

pps_num_exp_tile_rows_minus1 plus 1 specifies the number of explicitlyprovided tile row heights. The value of pps_num_exp_tile_rows_minus1shall be in the range of 0 to PicHeightInCtbsY−1, inclusive. Whenpps_no_pic_partition_flag is equal to 1, the value ofnum_tile_rows_minus1 is inferred to be equal to 0.

pps_tile_column_width_minus1[i] plus 1 specifies the width of the i-thtile column in units of CTBs for i in the range of 0 topps_num_exp_tile_columns_minus1, inclusive.pps_tile_column_width_minus1[pps_num_exp_tile_columns_minus1] is alsoused to derive the widths of the tile columns with index greater thanpps_num_exp_tile_columns_minus1 as specified. The value ofpps_tile_column_width_minus1[i] shall be in the range of 0 toPicWidthInCtbsY−1, inclusive. When not present, the value ofpps_tile_column_width_minus1 [0] is inferred to be equal toPicWidthInCtbsY−1.

pps_tile_row_height_minus1[i] plus 1 specifies the height of the i-thtile row in units of CTBs for i in the range of 0 topps_num_exp_tile_rows_minus1, inclusive. pps_tile_row_height_minus1[pps_num_exp_tile_rows_minus1] is also used to derive the heights of thetile rows with index greater than pps_num_exp_tile_rows_minus1 asspecified. The value of pps_tile_row_height_minus1 [i] shall be in therange of 0 to PicHeightInCtbsY−1, inclusive. When not present, the valueof pps_tile_row_height_minus1 [0] is inferred to be equal toPicHeightInCtbsY−1.

pps_loop_filter_across_tiles_enabled_flag equal to 1 specifies thatin-loop filtering operations across tile boundaries are enabled and maybe performed across tile boundaries in pictures referring to the PPS.pps_loop_filter_across_tiles_enabled_flag equal to 0 specifies thatin-loop filtering operations across tile boundaries are disabled and notperformed across tile boundaries in pictures referring to the PPS. Thein-loop filtering operations include the deblocking filter, sampleadaptive offset filter, and adaptive loop filter operations. When notpresent, the value of pps_loop_filter_across_tiles_enabled_flag isinferred to be equal to 1.

pps_rect_slice_flag equal to 0 specifies that tiles within each sliceare in raster scan order and the slice information is not signalled inPPS. pps_rect_slice_flag equal to 1 specifies that tiles within eachslice cover a rectangular region of the picture and the sliceinformation is signalled in the PPS. When not present,pps_rect_slice_flag is inferred to be equal to 1. Whensps_subpic_info_present_flag is equal to 1 orpps_mixed_nalu_types_in_pic_flag is equal to 1, the value ofpps_rect_slice_flag shall be equal to 1.

pps_single_slice_per_subpic_flag equal to 1 specifies that eachsubpicture consists of one and only one rectangular slice.pps_single_slice_per_subpic_flag equal to 0 specifies that eachsubpicture may consist of one or more rectangular slices. When notpresent, the value of pps_single_slice_per_subpic_flag is inferred to beequal to 1.

pps_num_slices_in_pic_minus1 plus 1 specifies the number of rectangularslices in each picture referring to the PPS. The value ofpps_num_slices_in_pic_minus1 shall be in the range of 0 toMaxSlicesPerPicture−1, inclusive, where MaxSlicesPerPicture is specifiedin Annex A. When pps_no_pic_partition_flag is equal to 1, the value ofpps_num_slices_in_pic_minus1 is inferred to be equal to 0. Whenpps_single_slice_per_subpic_flag is equal to 1, the value ofpps_num_slices_in_pic_minus1 is inferred to be equal tosps_num_subpics_minus1 pps_tile_idx_delta_present_flag equal to 0specifies that pps_tile_idx_delta_val[i] syntax elements are not presentin the PPS and all pictures referring to the PPS are partitioned intorectangular slice rows and rectangular slice columns in slice rasterorder. pps_tile_idx_delta_present_flag equal to 1 specifies thatpps_tile_idx_delta_val[i] syntax elements may be present in the PPS andall rectangular slices in pictures referring to the PPS are specified inthe order indicated by the values of the pps_tile_idx_delta_val[i] inincreasing values of i. When not present, the value ofpps_tile_idx_delta_present_flag is inferred to be equal to 0.

pps_slice_width_in_tiles_minus1[i] plus 1 specifies the width of thei-th rectangular slice in units of tile columns. The value ofpps_slice_width_in_tiles_minus1 [i] shall be in the range of 0 toNumTileColumns−1, inclusive. When not present, the value ofpps_slice_width_in_tiles_minus1 [i] is inferred to be equal to 0.

pps_slice_height_in_tiles_minus1[i] plus 1 specifies the height of thei-th rectangular slice in units of tile rows whenpps_num_exp_slices_in_tile[i] is equal to 0. The value ofpps_slice_height_in_tiles_minus1 [i] shall be in the range of 0 toNumTileRows−1, inclusive.

When pps_slice_height_in_tiles_minus1 [i] is not present, it is inferredas follows:

-   -   If SliceTopLeftTileIdx[i]/NumTileColumns is equal to        NumTileRows−1, the value of pps_slice_height_in_tiles_minus1 [i]        is inferred to be equal to 0.    -   Otherwise, the value of pps_slice_height_in_tiles_minus1 [i] is        inferred to be equal to pps_slice_height_in_tiles_minus1 [i−1].

pps_num_exp_slices_in_tile[i] specifies the number of explicitlyprovided slice heights for the slices in the tile containing the i-thslice (i.e., the tile with tile index equal to SliceTopLeftTileIdx[i]).The value of pps_num_exp_slices_in_tile[i] shall be in the range of 0 toRowHeight[SliceTopLeftTileIdx[i]/NumTileColumns]−1, inclusive. When notpresent, the value of pps_num_exp_slices_in_tile[i] is inferred to beequal to 0.

NOTE—If pps_num_exp_slices_in_tile[i] is equal to 0, the tile containingthe i-th slice is not split into multiple slices. Otherwise(pps_num_exp_slices_in_tile[i] is greater than 0), the tile containingthe i-th slice may or may not be split into multiple slices.

pps_exp_slice_height_in_ctus_minus1[i][j] plus 1 specifies the height ofthe j-th rectangular slice in the tile containing the i-th slice, inunits of CTU rows, for j in the range of 0 topps_num_exp_slices_in_tile[i]−1, inclusive, whenpps_num_exp_slices_in_tile[i] is greater than 0.pps_exp_slice_height_in_ctus_minus1 [i][pps_num_exp_slices_in_tile[i]]is also used to derive the heights of the rectangular slices in the tilecontaining the i-th slice with index greater thanpps_num_exp_slices_in_tile[i]−1 as specified. The value ofpps_exp_slice_height_in_ctus_minus1 [i][j] shall be in the range of 0 toRowHeight[SliceTopLeftTileIdx[i]/NumTileColumns]−1, inclusive.

pps_tile_idx_delta_val[i] specifies the difference between the tileindex of the tile containing the first CTU in the (i+1)-th rectangularslice and the tile index of the tile containing the first CTU in thei-th rectangular slice. The value of pps_tile_idx_delta_val[i] shall bein the range of −NumTilesInPic+1 to NumTilesInPic−1, inclusive. When notpresent, the value of pps_tile_idx_delta_val[i] is inferred to be equalto 0. When present, the value of pps_tile_idx_delta_val[i] shall not beequal to 0.

When pps_rect_slice_flag is equal to 1, it is a requirement of bitstreamconformance that, for any two slices, with picture-level slice indicesidxA and idxB, that belong to the same picture and differentsubpictures, when SubpicIdxForSlice[idxA] is less thanSubpicIdxForSlice[idxB], the value of idxA shall be less than idxB.

pps_loop_filter_across_slices_enabled_flag equal to 1 specifies thatin-loop filtering operations across slice boundaries are enabled and maybe performed across slice boundaries in pictures referring to the PPS.loop_filter_across_slice_enabled_flag equal to 0 specifies that in-loopfiltering operations across slice boundaries are disabled and notperformed across slice boundaries in pictures referring to the PPS. Thein-loop filtering operations include the deblocking filter, sampleadaptive offset filter, and adaptive loop filter operations. When notpresent, the value of pps_loop_filter_across_slices_enabled_flag isinferred to be equal to 0.

pps_cabac_init_present_flag equal to 1 specifies that sh_cabac_init_flagis present in slice headers referring to the PPS.pps_cabac_init_present_flag equal to 0 specifies that sh_cabac_init_flagis not present in slice headers referring to the PPS.

pps_num_ref_idx_default_active_minus1[i] plus 1, when i is equal to 0,specifies the inferred value of the variable NumRefIdxActive[0] for P orB slices with sh_num_ref_idx_active_override_flag equal to 0, and, wheni is equal to 1, specifies the inferred value of NumRefIdxActive[1] forB slices with sh_num_ref_idx_active_override_flag equal to 0. The valueof pps_num_ref_idx_default_active_minus1[i] shall be in the range of 0to 14, inclusive.

pps_rpl1_idx_present_flag equal to 0 specifies that rpl_sps_flag[1] andrpl_idx[1] are not present in the PH syntax structures or the sliceheaders for pictures referring to the PPS. pps_rpl1_idx_present_flagequal to 1 specifies that rpl_sps_flag[1] and rpl_idx[1] may be presentin the PH syntax structures or the slice headers for pictures referringto the PPS.

pps_init_qp_minus26 plus 26 specifies the initial value of SliceQpy foreach slice referring to the PPS. The initial value of SliceQpy ismodified at the picture level when a non-zero value of ph_qp_delta isdecoded or at the slice level when a non-zero value of sh_qp_delta isdecoded. The value of pps_init_qp_minus26 shall be in the range of−(26+QpBdOffset) to +37, inclusive.

pps_cu_qp_delta_enabled_flag equal to 1 specifies that theph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slicesyntax elements are present in PHs referring to the PPS, and thecu_qp_delta_abs and cu_qp_delta_sign_flag syntax elements may be presentin the transform unit syntax and the palette coding syntax.pps_cu_qp_delta_enabled_flag equal to 0 specifies that theph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slicesyntax elements are not present in PHs referring to the PPS, and thecu_qp_delta_abs and cu_qp_delta_sign_flag syntax elements are notpresent in the transform unit syntax or the palette coding syntax.

pps_chroma_tool_offsets_present_flag equal to 1 specifies that chromatool offsets related syntax elements are present in the PPS RBSP syntaxstructure and the chroma deblocking t_(c) and β offset syntax elementsare present in the PHs or the SHs of pictures referring to the PPS.pps_chroma_tool_offsets_present_flag equal to 0 specifies that chromatool offsets related syntax elements are not present in in the PPS RBSPsyntax structure and the chroma deblocking t_(c) and β offset syntaxelements are not present in the PHs or the SHs of pictures referring tothe PPS. When ChromaArrayType is equal to 0, the value ofpps_chroma_tool_offsets_present_flag shall be equal to 0.

pps_cb_qp_offset and pps_cr_qp_offset specify the offsets to the lumaquantization parameter Qp′_(Y) used for deriving Qp′_(Cb) and Qp′_(Cr),respectively. The values of pps_cb_qp_offset and pps_cr_qp_offset shallbe in the range of −12 to +12, inclusive. When ChromaArrayType is equalto 0, pps_cb_qp_offset and pps_cr_qp_offset are not used in the decodingprocess and decoders shall ignore their value. When not present, thevalues of pps_cb_qp_offset and pps_cr_qp_offset are inferred to be equalto 0.

pps_joint_cbcr_qp_offset_present_flag equal to 1 specifies thatpps_joint_cbcr_qp_offset_value and pps_joint_cbcr_qp_offset_list[i] arepresent in the PPS RBSP syntax structure.pps_joint_cbcr_qp_offset_present_flag equal to 0 specifies thatpps_joint_cbcr_qp_offset_value and pps_joint_cbcr_qp_offset_list[i] arenot present in the PPS RBSP syntax structure. When ChromaArrayType isequal to 0 or sps_joint_cbcr_enabled_flag is equal to 0, the value ofpps_joint_cbcr_qp_offset_present_flag shall be equal to 0. When notpresent, the value of pps_joint_cbcr_qp_offset_present_flag is inferredto be equal to 0.

pps_joint_cbcr_qp_offset_value specifies the offset to the lumaquantization parameter Qp′_(Y) used for deriving Qp′_(CbCr). The valueof pps_joint_cbcr_qp_offset_value shall be in the range of −12 to +12,inclusive. When ChromaArrayType is equal to 0 orsps_joint_cbcr_enabled_flag is equal to 0,pps_joint_cbcr_qp_offset_value is not used in the decoding process anddecoders shall ignore its value. Whenpps_joint_cbcr_qp_offset_present_flag is equal to 0,pps_joint_cbcr_qp_offset_value is not present and is inferred to beequal to 0.

pps_slice_chroma_qp_offsets_present_flag equal to 1 specifies that thesh_cb_qp_offset and sh_cr_qp_offset syntax elements are present in theassociated slice headers. pps_slice_chroma_qp_offsets_present_flag equalto 0 specifies that the sh_cb_qp_offset and sh_cr_qp_offset syntaxelements are not present in the associated slice headers. When notpresent, the value of pps_slice_chroma_qp_offsets_present_flag isinferred to be equal to 0.

pps_cu_chroma_qp_offset_list_enabled_flag equal to 1 specifies that theph_cu_chroma_qp_offset_subdiv_intra_slice andph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are present inPHs referring to the PPS and cu_chroma_qp_offset_flag may be present inthe transform unit syntax and the palette coding syntax.pps_cu_chroma_qp_offset_list_enabled_flag equal to 0 specifies that theph_cu_chroma_qp_offset_subdiv_intra_slice andph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are notpresent in PHs referring to the PPS and the cu_chroma_qp_offset_flag isnot present in the transform unit syntax and the palette coding syntax.When not present, the value of pps_cu_chroma_qp_offset_list_enabled_flagis inferred to be equal to 0.

pps_chroma_qp_offset_list_len_minus1 plus 1 specifies the number ofpps_cb_qp_offset_list[i], pps_cr_qp_offset_list[i], andpps_joint_cbcr_qp_offset_list[i], syntax elements that are present inthe PPS RBSP syntax structure. The value ofpps_chroma_qp_offset_list_len_minus1 shall be in the range of 0 to 5,inclusive.

pps_cb_qp_offset_list[i], pps_cr_qp_offset_list[i], andpps_joint_cbcr_qp_offset_list[i], specify offsets used in the derivationof Qp′_(Cb), Qp′_(Cr), and Qp′_(CbCr), respectively. The values ofpps_cb_qp_offset_list[i], pps_cr_qp_offset_list[i], andpps_joint_cbcr_qp_offset_list[i] shall be in the range of −12 to +12,inclusive. When pps_joint_cbcr_qp_offset_present_flag is equal to 0,pps_joint_cbcr_qp_offset_list[i] is not present and it is inferred to beequal to 0.

pps_weighted_pred_flag equal to 0 specifies that weighted prediction isnot applied to P slices referring to the PPS. pps_weighted_pred_flagequal to 1 specifies that weighted prediction is applied to P slicesreferring to the PPS. When sps_weighted_pred_flag is equal to 0, thevalue of pps_weighted_pred_flag shall be equal to 0.

pps_weighted_bipred_flag equal to 0 specifies that explicit weightedprediction is not applied to B slices referring to the PPS.pps_weighted_bipred_flag equal to 1 specifies that explicit weightedprediction is applied to B slices referring to the PPS. Whensps_weighted_bipred_flag is equal to 0, the value ofpps_weighted_bipred_flag shall be equal to 0.

pps_deblocking_filter_control_present_flag equal to 1 specifies thepresence of deblocking filter control syntax elements in the PPS.pps_deblocking_filter_control_present_flag equal to 0 specifies theabsence of deblocking filter control syntax elements in the PPS and thatthe deblocking filter is applied for all slices referring to the PPS,using 0-valued deblocking β and t_(C) offsets.

pps_deblocking_filter_override_enabled_flag equal to 1 specifies thepresence of ph_deblocking_filter_override_flag in the PHs referring tothe PPS or sh_deblocking_filter_override_flag in the slice headersreferring to the PPS. pps_deblocking_filter_override_enabled_flag equalto 0 specifies the absence of ph_deblocking_filter_override_flag in PHsreferring to the PPS or sh_deblocking_filter_override_flag in sliceheaders referring to the PPS. When not present, the value ofpps_deblocking_filter_override_enabled_flag is inferred to be equal to0.

pps_deblocking_filter_disabled_flag equal to 1 specifies that theoperation of deblocking filter is not applied for slices referring tothe PPS for which one of the following two conditions is true: 1)ph_deblocking_filter_disabled_flag andsh_deblocking_filter_disabled_flag are not present and inferred to beequal to 1 and 2) ph_deblockig_filter_disabled_flag orsh_deblocking_filter_disabled_flag is present and equal to 1, and alsospecifies that the operation of deblocking filter is applied for slicesreferring to the PPS for which one of the following two conditions istrue: 1) ph_deblocking_filter_disabled_flag andsh_deblocking_filter_disabled_flag are not present and inferred to beequal to 0 and 2) ph_deblocking_filter_disabled_flag orsh_deblocking_filter_disabled_flag is present and equal to 0.

pps_deblocking_filter_disabled_flag equal to 0 specifies that theoperation of the deblocking filter is applied for slices referring tothe PPS for which one of the following two conditions is true: 1)ph_deblocking_filter_disabled_flag andsh_deblocking_filter_disabled_flag are not present and 2)ph_deblocking_filter_disabled_flag or sh_deblocking_filter_disabled_flagis present and equal to 0, and also specifies that the operation ofdeblocking filter is not applied for slices referring to the PPS forwhich ph_deblocking_filter_disabled_flag orsh_deblocking_filter_disabled_flag is present and equal to 1.

When not present, the value of pps_deblocking_filter_disabled_flag isinferred to be equal to 0.

pps_dbf_info_in_ph_flag equal to 1 specifies that deblocking filterinformation is present in the PH syntax structure and not present inslice headers referring to the PPS that do not contain a PH syntaxstructure. pps_dbf_info_in_ph_flag equal to 0 specifies that deblockingfilter information is not present in the PH syntax structure and may bepresent in slice headers referring to the PPS. When not present, thevalue of pps_dbf_info_in_ph_flag is inferred to be equal to 0.

pps_luma_beta_offset_div2 and pps_luma_tc_offset_div2 specify thedefault deblocking parameter offsets for and tC (divided by 2) that areapplied to the luma component for slices referring to the PPS, unlessthe default deblocking parameter offsets are overridden by thedeblocking parameter offsets present in the picture headers or the sliceheaders of the slices referring to the PPS. The values ofpps_luma_beta_offset_div2 and pps_luma_tc_offset_div2 shall both be inthe range of −12 to 12, inclusive. When not present, the values ofpps_luma_beta_offset_div2 and pps_luma_tc_offset_div2 are both inferredto be equal to 0.

pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 specify the defaultdeblocking parameter offsets for β and tC (divided by 2) that areapplied to the Cb component for slices referring to the PPS, unless thedefault deblocking parameter offsets are overridden by the deblockingparameter offsets present in the picture headers or the slice headers ofthe slices referring to the PPS. The values of pps_cb_beta_offset_div2and pps_cb_tc_offset_div2 shall both be in the range of −12 to 12,inclusive. When not present, the values of pps_cb_beta_offset_div2 andpps_cb_tc_offset_div2 are inferred to be equal topps_luma_beta_offset_div2 and pps_luma_tc_offset_div2, respectively.

pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 specify the defaultdeblocking parameter offsets for β and tC (divided by 2) that areapplied to the Cr component for slices referring to the PPS, unless thedefault deblocking parameter offsets are overridden by the deblockingparameter offsets present in the picture headers or the slice headers ofthe slices referring to the PPS. The values of pps_cr_beta_offset_div2and pps_cr_tc_offset_div2 shall both be in the range of −12 to 12,inclusive. When not present, the values of pps_cr_beta_offset_div2 andpps_cr_tc_offset_div2 are inferred to be equal topps_luma_beta_offset_div2 and pps_luma_tc_offset_div2, respectively.

pps_rpl_info_in_ph_flag equal to 1 specifies that reference picture listinformation is present in the PH syntax structure and not present inslice headers referring to the PPS that do not contain a PH syntaxstructure. pps_rpl_info_in_ph_flag equal to 0 specifies that referencepicture list information is not present in the PH syntax structure andmay be present in slice headers referring to the PPS. When not present,the value of pps_rpl_info_in_ph_flag is inferred to be equal to 0.

pps_sao_info_in_ph_flag equal to 1 specifies that SAO filter informationis present in the PH syntax structure and not present in slice headersreferring to the PPS that do not contain a PH syntax structure.pps_sao_info_in_ph_flag equal to 0 specifies that SAO filter informationis not present in the PH syntax structure and may be present in sliceheaders referring to the PPS. When not present, the value ofpps_sao_info_in_ph_flag is inferred to be equal to 0.

pps_alf_info_in_ph_flag equal to 1 specifies that ALF information ispresent in the PH syntax structure and not present in slice headersreferring to the PPS that do not contain a PH syntax structure.pps_alf_info_in_ph_flag equal to 0 specifies that ALF information is notpresent in the PH syntax structure and may be present in slice headersreferring to the PPS. When not present, the value ofpps_alf_info_in_ph_flag is inferred to be equal to 0.

pps_wp_info_in_ph_flag equal to 1 specifies that weighted predictioninformation may be present in the PH syntax structure and not present inslice headers referring to the PPS that do not contain a PH syntaxstructure. pps_wp_info_in_ph_flag equal to 0 specifies that weightedprediction information is not present in the PH syntax structure and maybe present in slice headers referring to the PPS. When not present, thevalue of pps_wp_info_in_ph_flag is inferred to be equal to 0.

pps_qp_delta_info_in_ph_flag equal to 1 specifies that QP deltainformation is present in the PH syntax structure and not present inslice headers referring to the PPS that do not contain a PH syntaxstructure. pps_qp_delta_info_in_ph_flag equal to 0 specifies that QPdelta information is not present in the PH syntax structure and ispresent in slice headers referring to the PPS. When not present, thevalue of pps_qp_delta_info_in_ph_flag is inferred to be equal to 0.

pps_ref_wraparound_enabled_flag equal to 1 specifies that horizontalwrap-around motion compensation is enabled and may be applied in interprediction in decoding of pictures referring to the PPS.pps_ref_wraparound_enabled_flag equal to 0 specifies that horizontalwrap-around motion compensation is disabled and not applied in interprediction in decoding of pictures referring to the PPS.

When sps_ref_wraparound_enabled_flag is equal to 0 or the value ofCtbSizeY/MinCbSizeY+1 is greater thanpps_pic_width_in_luma_samples/MinCbSizeY−1, the value ofpps_ref_wraparound_enabled_flag shall be equal to 0.

pps_pic_width_minus_wraparound_offset specifies the difference betweenthe picture width and the offset used for computing the horizontalwrap-around position in units of MinCbSizeY luma samples. The value ofpps_pic_width_minus_wraparound_offset shall be less than or equal to(pps_pic_width_in_luma_samples/MinCbSizeY)−(CtbSizeY/MinCbSizeY)−2.

The variable PpsRefWraparoundOffset is set equal topps_pic_width_in_luma_samples/MinCbSizeY−pps_pic_width_minus_wraparound_offset.

pps_picture_header_extension_present_flag equal to 0 specifies that noPH extension syntax elements are present in PHs referring to the PPS.pps_picture_header_extension_present_flag equal to 1 specifies that PHextension syntax elements are present in PHs referring to the PPS.pps_picture_header_extension_present_flag shall be equal to 0 inbitstreams conforming to this version of this Specification.

pps_slice_header_extension_present_flag equal to 0 specifies that noslice header extension syntax elements are present in the slice headersfor coded pictures referring to the PPS.pps_slice_header_extension_present_flag equal to 1 specifies that sliceheader extension syntax elements are present in the slice headers forcoded pictures referring to the PPS.pps_slice_header_extension_present_flag shall be equal to 0 inbitstreams conforming to this version of this Specification.

pps_extension_flag equal to 0 specifies that no pps_extension_data_flagsyntax elements are present in the PPS RBSP syntax structure.pps_extension_flag equal to 1 specifies that there arepps_extension_data_flag syntax elements present in the PPS RBSP syntaxstructure.

pps_extension_data_flag may have any value. Its presence and value donot affect decoder conformance to profiles specified in this version ofthis Specification. Decoders conforming to this version of thisSpecification shall ignore all pps_extension_data_flag syntax elements.

According to the syntax provided in Table 3, in JVET-R2001,seq_parameter_set_rbsp( ) includes syntax element sps_reserved_zero_4bits which includes reserved bits for future use. Further,seq_parameter_set_rbsp( ) has an extension mechanism which can be usedin the future if needed. Also, no such reserved bits are included in PPSor VPS. Thus, syntax element sps_reserved_zero_4 bits may waste bits andbe inconsistent with other parameter sets. According to the techniquesdescribed herein, seq_parameter_set_rbsp( ) may be modified to removesyntax element sps_reserved_zero_4 bits. Further, in one example,according to the techniques herein, fewer reserved bits (for example,fewer than 4) may be included in seq_parameter_set_rbsp( ) and/orreserved bits may be added to pic_parameter_set_rbsp( ).

FIG. 1 is a block diagram illustrating an example of a system that maybe configured to code (i.e., encode and/or decode) video data accordingto one or more techniques of this disclosure. System 100 represents anexample of a system that may encapsulate video data according to one ormore techniques of this disclosure. As illustrated in FIG. 1, system 100includes source device 102, communications medium 110, and destinationdevice 120. In the example illustrated in FIG. 1, source device 102 mayinclude any device configured to encode video data and transmit encodedvideo data to communications medium 110. Destination device 120 mayinclude any device configured to receive encoded video data viacommunications medium 110 and to decode encoded video data. Sourcedevice 102 and/or destination device 120 may include computing devicesequipped for wired and/or wireless communications and may include, forexample, set top boxes, digital video recorders, televisions, desktop,laptop or tablet computers, gaming consoles, medical imagining devices,and mobile devices, including, for example, smartphones, cellulartelephones, personal gaming devices.

Communications medium 110 may include any combination of wireless andwired communication media, and/or storage devices. Communications medium110 may include coaxial cables, fiber optic cables, twisted pair cables,wireless transmitters and receivers, routers, switches, repeaters, basestations, or any other equipment that may be useful to facilitatecommunications between various devices and sites. Communications medium110 may include one or more networks. For example, communications medium110 may include a network configured to enable access to the World WideWeb, for example, the Internet. A network may operate according to acombination of one or more telecommunication protocols.Telecommunications protocols may include proprietary aspects and/or mayinclude standardized telecommunication protocols. Examples ofstandardized telecommunications protocols include Digital VideoBroadcasting (DVB) standards, Advanced Television Systems Committee(ATSC) standards, Integrated Services Digital Broadcasting (ISDB)standards, Data Over Cable Service Interface Specification (DOCSIS)standards, Global System Mobile Communications (GSM) standards, codedivision multiple access (CDMA) standards, 3rd Generation PartnershipProject (3GPP) standards, European Telecommunications StandardsInstitute (ETSI) standards, Internet Protocol (IP) standards, WirelessApplication Protocol (WAP) standards, and Institute of Electrical andElectronics Engineers (IEEE) standards.

Storage devices may include any type of device or storage medium capableof storing data. A storage medium may include a tangible ornon-transitory computer-readable media. A computer readable medium mayinclude optical discs, flash memory, magnetic memory, or any othersuitable digital storage media. In some examples, a memory device orportions thereof may be described as non-volatile memory and in otherexamples portions of memory devices may be described as volatile memory.Examples of volatile memories may include random access memories (RAM),dynamic random access memories (DRAM), and static random access memories(SRAM). Examples of non-volatile memories may include magnetic harddiscs, optical discs, floppy discs, flash memories, or forms ofelectrically programmable memories (EPROM) or electrically erasable andprogrammable (EEPROM) memories. Storage device(s) may include memorycards (e.g., a Secure Digital (SD) memory card), internal/external harddisk drives, and/or internal/external solid state drives. Data may bestored on a storage device according to a defined file format.

FIG. 4 is a conceptual drawing illustrating an example of componentsthat may be included in an implementation of system 100. In the exampleimplementation illustrated in FIG. 4, system 100 includes one or morecomputing devices 402A-402N, television service network 404, televisionservice provider site 406, wide area network 408, local area network410, and one or more content provider sites 412A-412N. Theimplementation illustrated in FIG. 4 represents an example of a systemthat may be configured to allow digital media content, such as, forexample, a movie, a live sporting event, etc., and data and applicationsand media presentations associated therewith to be distributed to andaccessed by a plurality of computing devices, such as computing devices402A-402N. In the example illustrated in FIG. 4, computing devices402A-402N may include any device configured to receive data from one ormore of television service network 404, wide area network 408, and/orlocal area network 410. For example, computing devices 402A-402N may beequipped for wired and/or wireless communications and may be configuredto receive services through one or more data channels and may includetelevisions, including so-called smart televisions, set top boxes, anddigital video recorders. Further, computing devices 402A-402N mayinclude desktop, laptop, or tablet computers, gaming consoles, mobiledevices, including, for example, “smart” phones, cellular telephones,and personal gaming devices.

Television service network 404 is an example of a network configured toenable digital media content, which may include television services, tobe distributed. For example, television service network 404 may includepublic over-the-air television networks, public or subscription-basedsatellite television service provider networks, and public orsubscription-based cable television provider networks and/or over thetop or Internet service providers. It should be noted that although insome examples television service network 404 may primarily be used toenable television services to be provided, television service network404 may also enable other types of data and services to be providedaccording to any combination of the telecommunication protocolsdescribed herein. Further, it should be noted that in some examples,television service network 404 may enable two-way communications betweentelevision service provider site 406 and one or more of computingdevices 402A-402N. Television service network 404 may comprise anycombination of wireless and/or wired communication media. Televisionservice network 404 may include coaxial cables, fiber optic cables,twisted pair cables, wireless transmitters and receivers, routers,switches, repeaters, base stations, or any other equipment that may beuseful to facilitate communications between various devices and sites.Television service network 404 may operate according to a combination ofone or more telecommunication protocols. Telecommunications protocolsmay include proprietary aspects and/or may include standardizedtelecommunication protocols. Examples of standardized telecommunicationsprotocols include DVB standards, ATSC standards, ISDB standards, DTMBstandards, DMB standards, Data Over Cable Service InterfaceSpecification (DOCSIS) standards, HbbTV standards, W3C standards, andUPnP standards.

Referring again to FIG. 4, television service provider site 406 may beconfigured to distribute television service via television servicenetwork 404. For example, television service provider site 406 mayinclude one or more broadcast stations, a cable television provider, ora satellite television provider, or an Internet-based televisionprovider. For example, television service provider site 406 may beconfigured to receive a transmission including television programmingthrough a satellite uplink/downlink. Further, as illustrated in FIG. 4,television service provider site 406 may be in communication with widearea network 408 and may be configured to receive data from contentprovider sites 412A-412N. It should be noted that in some examples,television service provider site 406 may include a television studio andcontent may originate therefrom.

Wide area network 408 may include a packet based network and operateaccording to a combination of one or more telecommunication protocols.Telecommunications protocols may include proprietary aspects and/or mayinclude standardized telecommunication protocols. Examples ofstandardized telecommunications protocols include Global System MobileCommunications (GSM) standards, code division multiple access (CDMA)standards, 3rd Generation Partnership Project (3GPP) standards, EuropeanTelecommunications Standards Institute (ETSI) standards, Europeanstandards (EN), IP standards, Wireless Application Protocol (WAP)standards, and Institute of Electrical and Electronics Engineers (IEEE)standards, such as, for example, one or more of the IEEE 802 standards(e.g., Wi-Fi). Wide area network 408 may comprise any combination ofwireless and/or wired communication media. Wide area network 408 mayinclude coaxial cables, fiber optic cables, twisted pair cables,Ethernet cables, wireless transmitters and receivers, routers, switches,repeaters, base stations, or any other equipment that may be useful tofacilitate communications between various devices and sites. In oneexample, wide area network 408 may include the Internet. Local areanetwork 410 may include a packet based network and operate according toa combination of one or more telecommunication protocols. Local areanetwork 410 may be distinguished from wide area network 408 based onlevels of access and/or physical infrastructure. For example, local areanetwork 410 may include a secure home network.

Referring again to FIG. 4, content provider sites 412A-412N representexamples of sites that may provide multimedia content to televisionservice provider site 406 and/or computing devices 402A-402N. Forexample, a content provider site may include a studio having one or morestudio content servers configured to provide multimedia files and/orstreams to television service provider site 406. In one example, contentprovider sites 412A-412N may be configured to provide multimedia contentusing the IP suite. For example, a content provider site may beconfigured to provide multimedia content to a receiver device accordingto Real Time Streaming Protocol (RTSP), HTTP, or the like. Further,content provider sites 412A-412N may be configured to provide data,including hypertext based content, and the like, to one or more ofreceiver devices computing devices 402A-402N and/or television serviceprovider site 406 through wide area network 408. Content provider sites412A-412N may include one or more web servers. Data provided by dataprovider site 412A-412N may be defined according to data formats.

Referring again to FIG. 1, source device 102 includes video source 104,video encoder 106, data encapsulator 107, and interface 108. Videosource 104 may include any device configured to capture and/or storevideo data. For example, video source 104 may include a video camera anda storage device operably coupled thereto. Video encoder 106 may includeany device configured to receive video data and generate a compliantbitstream representing the video data. A compliant bitstream may referto a bitstream that a video decoder can receive and reproduce video datatherefrom. Aspects of a compliant bitstream may be defined according toa video coding standard. When generating a compliant bitstream videoencoder 106 may compress video data. Compression may be lossy(discernible or indiscernible to a viewer) or lossless. FIG. 5 is ablock diagram illustrating an example of video encoder 500 that mayimplement the techniques for encoding video data described herein. Itshould be noted that although example video encoder 500 is illustratedas having distinct functional blocks, such an illustration is fordescriptive purposes and does not limit video encoder 500 and/orsub-components thereof to a particular hardware or softwarearchitecture. Functions of video encoder 500 may be realized using anycombination of hardware, firmware, and/or software implementations.

Video encoder 500 may perform intra prediction coding and interprediction coding of picture areas, and, as such, may be referred to asa hybrid video encoder. In the example illustrated in FIG. 5, videoencoder 500 receives source video blocks. In some examples, source videoblocks may include areas of picture that has been divided according to acoding structure. For example, source video data may includemacroblocks, CTUs, CBs, sub-divisions thereof, and/or another equivalentcoding unit. In some examples, video encoder 500 may be configured toperform additional sub-divisions of source video blocks. It should benoted that the techniques described herein are generally applicable tovideo coding, regardless of how source video data is partitioned priorto and/or during encoding. In the example illustrated in FIG. 5, videoencoder 500 includes summer 502, transform coefficient generator 504,coefficient quantization unit 506, inverse quantization and transformcoefficient processing unit 508, summer 510, intra prediction processingunit 512, inter prediction processing unit 514, filter unit 516, andentropy encoding unit 518. As illustrated in FIG. 5, video encoder 500receives source video blocks and outputs a bitstream.

In the example illustrated in FIG. 5, video encoder 500 may generateresidual data by subtracting a predictive video block from a sourcevideo block. The selection of a predictive video block is described indetail below. Summer 502 represents a component configured to performthis subtraction operation. In one example, the subtraction of videoblocks occurs in the pixel domain. Transform coefficient generator 504applies a transform, such as a discrete cosine transform (DCT), adiscrete sine transform (DST), or a conceptually similar transform, tothe residual block or sub-divisions thereof (e.g., four 8×8 transformsmay be applied to a 16×16 array of residual values) to produce a set ofresidual transform coefficients. Transform coefficient generator 504 maybe configured to perform any and all combinations of the transformsincluded in the family of discrete trigonometric transforms, includingapproximations thereof. Transform coefficient generator 504 may outputtransform coefficients to coefficient quantization unit 506. Coefficientquantization unit 506 may be configured to perform quantization of thetransform coefficients. The quantization process may reduce the bitdepth associated with some or all of the coefficients. The degree ofquantization may alter the rate-distortion (i.e., bit-rate vs. qualityof video) of encoded video data. The degree of quantization may bemodified by adjusting a quantization parameter (QP). A quantizationparameter may be determined based on slice level values and/or CU levelvalues (e.g., CU delta QP values). QP data may include any data used todetermine a QP for quantizing a particular set of transformcoefficients. As illustrated in FIG. 5, quantized transform coefficients(which may be referred to as level values) are output to inversequantization and transform coefficient processing unit 508. Inversequantization and transform coefficient processing unit 508 may beconfigured to apply an inverse quantization and an inversetransformation to generate reconstructed residual data. As illustratedin FIG. 5, at summer 510, reconstructed residual data may be added to apredictive video block. In this manner, an encoded video block may bereconstructed and the resulting reconstructed video block may be used toevaluate the encoding quality for a given prediction, transformation,and/or quantization. Video encoder 500 may be configured to performmultiple coding passes (e.g., perform encoding while varying one or moreof a prediction, transformation parameters, and quantizationparameters). The rate-distortion of a bitstream or other systemparameters may be optimized based on evaluation of reconstructed videoblocks. Further, reconstructed video blocks may be stored and used asreference for predicting subsequent blocks.

Referring again to FIG. 5, intra prediction processing unit 512 may beconfigured to select an intra prediction mode for a video block to becoded. Intra prediction processing unit 512 may be configured toevaluate a frame and determine an intra prediction mode to use to encodea current block. As described above, possible intra prediction modes mayinclude planar prediction modes, DC prediction modes, and angularprediction modes. Further, it should be noted that in some examples, aprediction mode for a chroma component may be inferred from a predictionmode for a luma prediction mode. Intra prediction processing unit 512may select an intra prediction mode after performing one or more codingpasses. Further, in one example, intra prediction processing unit 512may select a prediction mode based on a rate-distortion analysis. Asillustrated in FIG. 5, intra prediction processing unit 512 outputsintra prediction data (e.g., syntax elements) to entropy encoding unit518 and transform coefficient generator 504. As described above, atransform performed on residual data may be mode dependent (e.g., asecondary transform matrix may be determined based on a predictionmode).

Referring again to FIG. 5, inter prediction processing unit 514 may beconfigured to perform inter prediction coding for a current video block.Inter prediction processing unit 514 may be configured to receive sourcevideo blocks and calculate a motion vector for PUs of a video block. Amotion vector may indicate the displacement of a prediction unit of avideo block within a current video frame relative to a predictive blockwithin a reference frame. Inter prediction coding may use one or morereference pictures. Further, motion prediction may be uni-predictive(use one motion vector) or bi-predictive (use two motion vectors). Interprediction processing unit 514 may be configured to select a predictiveblock by calculating a pixel difference determined by, for example, sumof absolute difference (SAD), sum of square difference (SSD), or otherdifference metrics. As described above, a motion vector may bedetermined and specified according to motion vector prediction. Interprediction processing unit 514 may be configured to perform motionvector prediction, as described above. Inter prediction processing unit514 may be configured to generate a predictive block using the motionprediction data. For example, inter prediction processing unit 514 maylocate a predictive video block within a frame buffer (not shown in FIG.5). It should be noted that inter prediction processing unit 514 mayfurther be configured to apply one or more interpolation filters to areconstructed residual block to calculate sub-integer pixel values foruse in motion estimation. Inter prediction processing unit 514 mayoutput motion prediction data for a calculated motion vector to entropyencoding unit 518.

Referring again to FIG. 5, filter unit 516 receives reconstructed videoblocks and coding parameters and outputs modified reconstructed videodata. Filter unit 516 may be configured to perform deblocking and/orSample Adaptive Offset (SAO) filtering. SAO filtering is a non-linearamplitude mapping that may be used to improve reconstruction by addingan offset to reconstructed video data. It should be noted that asillustrated in FIG. 5, intra prediction processing unit 512 and interprediction processing unit 514 may receive modified reconstructed videoblock via filter unit 216. Entropy encoding unit 518 receives quantizedtransform coefficients and predictive syntax data (i.e., intraprediction data and motion prediction data). It should be noted that insome examples, coefficient quantization unit 506 may perform a scan of amatrix including quantized transform coefficients before thecoefficients are output to entropy encoding unit 518. In other examples,entropy encoding unit 518 may perform a scan. Entropy encoding unit 518may be configured to perform entropy encoding according to one or moreof the techniques described herein. In this manner, video encoder 500represents an example of a device configured to generate encoded videodata according to one or more techniques of this disclosure.

Referring again to FIG. 1, data encapsulator 107 may receive encodedvideo data and generate a compliant bitstream, e.g., a sequence of NALunits according to a defined data structure. A device receiving acompliant bitstream can reproduce video data therefrom. Further, asdescribed above, sub-bitstream extraction may refer to a process where adevice receiving a compliant bitstream forms a new compliant bitstreamby discarding and/or modifying data in the received bitstream. It shouldbe noted that the term conforming bitstream may be used in place of theterm compliant bitstream. In one example, data encapsulator 107 may beconfigured to generate syntax according to one or more techniquesdescribed herein. It should be noted that data encapsulator 107 need notnecessary be located in the same physical device as video encoder 106.For example, functions described as being performed by video encoder 106and data encapsulator 107 may be distributed among devices illustratedin FIG. 4.

As described above, the signaling sequence parameter set information inJVET-R2001 may be less than ideal. That is, syntax elementsps_reserved_zero_4 bits may waste bits and be inconsistent with otherparameter sets. In one example, according to the techniques herein,seq_parameter_set_rbsp( ) may be modified to remove syntax elementsps_reserved_zero_4 bits. Table 5 illustrates an example of the relevantportion of a seq_parameter_set_rbsp( ) syntax structure which may besignaled and/or parsed according to the techniques herein. With respectto Table 5 the semantics may be based on the semantics provided above.It should be noted that in Table 5 syntax elements sps_chroma_format_idcand sps_log2_ctu_size_minus5 immediately follow syntax elementsps_max_sublayers_minus1.

TABLE 5 seq_parameter_set_rbsp( ) { Descriptor  sps_seq_parameter_set_idu(4)  sps_video_parameter_set_id u(4)  sps_max_sublayers_minus1 u(3) sps_chroma_format_idc u(2)  sps_log2_ctu_size_minus5 u(2) sps_ptl_dpb_hrd_params_present_flag u(1)  if(sps_ptl_dpb_hrd_params_present_flag )   profile_tier_level( 1,sps_max_sublayers_minus1 )  sps_gdr_enabled_flag u(1) sps_ref_pic_resampling_enabled_flag u(1)  if( sps_refpic_resampling_enabled_flag )   sps_res_change_in_clvs_allowed_flag u(1) sps_pic_width_max_in_luma_samples ue(v) sps_pic_height_max_in_luma_samples ue(v)  sps_conformance_window_flagu(1)  if( sps_conformance_window_flag ) {   sps_conf_win_left_offsetue(v)   sps_conf_win_right_offset ue(v)   sps_conf_win_top_offset ue(v)  sps_conf_win_bottom_offset ue(v)  }  sps_subpic_info_present_flag u(1). . . }

In another example, other syntax elements may be signaled in place ofsome reserved bits in seq_parameter_set_rbsp( ). Table 6 illustrates anexample of the relevant portion of a seq_parameter_set_rbsp( ) syntaxstructure which may be signaled and/or parsed according to thetechniques herein.

TABLE 6 seq_parameter_set_rbsp( ) { Descriptor  sps_seq_parameter_set_idu(4)  sps_video_parameter_set_id u(4)  sps_max_sublayers_minus1 u(3) sps_gdr_enabled_flag u(1)  sps_chroma_format_idc u(2) sps_reserved_zero_1bit u(1)  sps_ptl_dpb_hrd_params_present_flag u(1) if( sps_ptl_dpb_hrd_params_present_flag )   profile_tier_level( 1,sps_max_sublayers_minus1 )  sps_ref_pic_resampling_enabled_flag u(1) if( sps_ref pic_resampling_enabled_flag )  sps_res_change_in_clvs_allowed_flag u(1) sps_pic_width_max_in_luma_samples ue(v) sps_pic_height_max_in_luma_samples ue(v)  sps_conformance_window_flagu(1)  if( sps_conformance_window_flag ) {   sps_conf_win_left_offsetue(v)   sps_conf_win_right_offset ue(v)   sps_conf_win_top_offset ue(v)  sps_conf_win_bottom_offset ue(v)  }  sps_log2_ctu_size_minus5 u(2) sps_subpic_info_present_flag u(1) . . . }

With respect to Table 6, the semantics may be based on the semanticsprovided above with the following semantics for sps_reserved_zero_1bit:

sps_reserved_zero_1bit shall be equal to 0 in bitstreams conforming tothis version of this Specification. Other value forsps_reserved_zero_1bit is reserved for future use by ITU-T|ISO/IEC.

In another example, reserved bits may be included in apic_parameter_set_rbsp( ) Table 7 illustrates an example of the relevantportion of a pic_parameter_set_rbsp( ) syntax structure which may besignaled and/or parsed according to the techniques herein.

TABLE 7 pic_parameter_set_rbsp( ) { Descriptor  pps_pic_parameter_set_idu(6)  pps_seq_parameter_set_id u(4)  pps_mixed_nalu_types_in_pic_flagu(1)  pps_reserved_zero_7bits u(7)  pps_pic_width_in_luma_samples ue(v) pps_pic_height_in_luma_samples ue(v)  pps_conformance_window_flag u(1). . . }

With respect to Table 7, the semantics may be based on the semanticsprovided above with the following semantics for pps_reserved_zero_7bits:

pps_reserved_zero_7 bits shall be equal to 0 in bitstreams conforming tothis version of this Specification. Other values for pps_reserved_zero_7bits are reserved for future use by ITU-T|ISO/IEC.

Further, in some examples, a number of fixed length syntax elements canbe moved in a PPS to be before the first ue(v) coded syntax element,i.e., syntax element pps_pic_width_in_luma_samples. A combination ofthese syntax elements and reserve bits may be used to ensure bytealignment before the first ue(v) coded syntax element, e.g.pps_pic_width_in_luma_samples).

It should be noted that the VVC design allows some sharing of SPSsacross layers. However, there are constraints with respect to thissharing. In JVET-R2001, syntax element sps_seq_parameter_set_id is codedas u(4). As a result, a maximum of 16 SPSs with unique values ofsps_seq_parameter_set_id are possible. In contrast, in ITU-T H.265,syntax element sps_seq_parameter_set_id is coded as a ue(v) code, whichallows for a higher number of SPSs for future extensibility. In oneexample, according to the techniques herein, a value of 15 forsps_seq_parameter_set_id may be kept as a reserved value for futureextensibility. That is, in one example, the semantics of syntax elementsps_seq_parameter_set_id and pps_seq_parameter_set_id may be based onthe following:

sps_seq_parameter_set_id provides an identifier for the SPS forreference by other syntax elements. The value ofsps_seq_parameter_set_id shall be in the range of 0 to 14, inclusive.The value 15 for sps_seq_parameter_set_id is reserved for future use byITU-T|ISO/IEC.

SPS NAL units, regardless of the nuh_layer_id values, share the samevalue space of sps_seq_parameter_set_id. Let spsLayerId be the value ofthe nuh_layer_id of a particular SPS NAL unit, and vclLayerId be thevalue of the nuh_layer_id of a particular VCL NAL unit. The particularVCL NAL unit shall not refer to the particular SPS NAL unit unlessspsLayerId is less than or equal to vclLayerId and all OLSs specified bythe VPS that contain the layer with nuh_layer_id equal to vclLayerIdalso contain the layer with nuh_layer_id equal to spslayerId.

pps_seq_parameter_set_id specifies the value of sps_seq_parameter_set_idfor the SPS. The value of pps_seq_parameter_set_id shall be in the rangeof 0 to 14, inclusive. The value of pps_seq_parameter_set_id shall bethe same in all PPSs that are referred to by coded pictures in a CLVS.

Additionally, in one example the value 63, may be kept reserved forsyntax element pps_pic_parameter_set_id for future extensions. It shouldbe noted that in JVET-R2001 syntax element pps_pic_parameter_set_id iscoded as a u(6) code and in ITU-T H.265 syntax elementpps_pic_parameter_set_id is coded as a ue(v) code. In one example,according to the techniques herein, the semantics of syntax elementpps_pic_parameter_set_id and ph_pic_parameter_set_id, which is includedin a picture header syntax structure, may be based on the following:

A PPS RBSP shall be available to the decoding process prior to it beingreferenced, included in at least one AU with TemporalId less than orequal to the TemporalId of the PPS NAL unit or provided through externalmeans. All PPS NAL units with a particular value ofpps_pic_parameter_set_id within a PU shall have the same content.

pps_pic_parameter_set_id identifies the PPS for reference by othersyntax elements.

PPS NAL units, regardless of the nuh_layer_id values, share the samevalue space of pps_pic_parameter_set_id. The value ofpps_pic_parameter_set_id shall be in the range of 0 to 62, inclusive.The value 63 for pps_pic_parameter_set_id is reserved for future use byITU-T|ISO/IEC.

Let ppsLayerId be the value of the nuh_layer_id of a particular PPS NALunit, and vclLayerId be the value of the nuh_layer_id of a particularVCL NAL unit. The particular VCL NAL unit shall not refer to theparticular PPS NAL unit unless ppsLayerId is less than or equal tovclLayerId and all OLSs specified by the VPS that contain the layer withnuh_layer_id equal to vclLayerId also contain the layer withnuh_layer_id equal to ppslayerId.

NOTE—In a CVS that contains only one layer, the nuh_layer_id ofreferenced PPSs is equal to the nuh_layer_id of the VCL NAL units.

ph_pic_parameter_set_id specifies the value of pps_pic_parameter_set_idfor the PPS in use. The value of ph_pic_parameter_set_id shall be in therange of 0 to 62, inclusive.

It is a requirement of bitstream conformance that the value ofTemporalId of the PH shall be greater than or equal to the value ofTemporalId of the PPS that has pps_pic_parameter_set_id equal toph_pic_parameter_set_id.

In this manner, source device 102 represents an example of a deviceconfigured to signal a syntax element in a sequence parameter set syntaxstructure specifying a maximum number of temporal sublayers that may bepresent in each coded video sequence referring to the sequence parameterset, signal a syntax element specifying a chroma sampling, and signal asyntax element specifying a luma coding tree block size, wherein thesyntax element specifying a chroma sampling and the syntax elementspecifying a luma coding tree block size immediately follow the syntaxelement specifying a maximum number of temporal sublayers.

Referring again to FIG. 1, interface 108 may include any deviceconfigured to receive data generated by data encapsulator 107 andtransmit and/or store the data to a communications medium. Interface 108may include a network interface card, such as an Ethernet card, and mayinclude an optical transceiver, a radio frequency transceiver, or anyother type of device that can send and/or receive information. Further,interface 108 may include a computer system interface that may enable afile to be stored on a storage device. For example, interface 108 mayinclude a chipset supporting Peripheral Component Interconnect (PCI) andPeripheral Component Interconnect Express (PCIe) bus protocols,proprietary bus protocols, Universal Serial Bus (USB) protocols, I²C, orany other logical and physical structure that may be used tointerconnect peer devices.

Referring again to FIG. 1, destination device 120 includes interface122, data decapsulator 123, video decoder 124, and display 126.Interface 122 may include any device configured to receive data from acommunications medium. Interface 122 may include a network interfacecard, such as an Ethernet card, and may include an optical transceiver,a radio frequency transceiver, or any other type of device that canreceive and/or send information. Further, interface 122 may include acomputer system interface enabling a compliant video bitstream to beretrieved from a storage device. For example, interface 122 may includea chipset supporting PCI and PCIe bus protocols, proprietary busprotocols, USB protocols, I²C, or any other logical and physicalstructure that may be used to interconnect peer devices. Datadecapsulator 123 may be configured to receive and parse any of theexample syntax structures described herein.

Video decoder 124 may include any device configured to receive abitstream (e.g., a sub-bitstream extraction) and/or acceptablevariations thereof and reproduce video data therefrom. Display 126 mayinclude any device configured to display video data. Display 126 maycomprise one of a variety of display devices such as a liquid crystaldisplay (LCD), a plasma display, an organic light emitting diode (OLED)display, or another type of display. Display 126 may include a HighDefinition display or an Ultra High Definition display. It should benoted that although in the example illustrated in FIG. 1, video decoder124 is described as outputting data to display 126, video decoder 124may be configured to output video data to various types of devicesand/or sub-components thereof. For example, video decoder 124 may beconfigured to output video data to any communication medium, asdescribed herein.

FIG. 6 is a block diagram illustrating an example of a video decoderthat may be configured to decode video data according to one or moretechniques of this disclosure (e.g., the decoding process forreference-picture list construction described above). In one example,video decoder 600 may be configured to decode transform data andreconstruct residual data from transform coefficients based on decodedtransform data. Video decoder 600 may be configured to perform intraprediction decoding and inter prediction decoding and, as such, may bereferred to as a hybrid decoder. Video decoder 600 may be configured toparse any combination of the syntax elements described above in Tables1-7. Video decoder 600 may decode a picture based on or according to theprocesses described above, and further based on parsed values in Tables1-7.

In the example illustrated in FIG. 6, video decoder 600 includes anentropy decoding unit 602, inverse quantization unit 604, inversetransform coefficient processing unit 606, intra prediction processingunit 608, inter prediction processing unit 610, summer 612, post filterunit 614, and reference buffer 616. Video decoder 600 may be configuredto decode video data in a manner consistent with a video coding system.It should be noted that although example video decoder 600 isillustrated as having distinct functional blocks, such an illustrationis for descriptive purposes and does not limit video decoder 600 and/orsub-components thereof to a particular hardware or softwarearchitecture. Functions of video decoder 600 may be realized using anycombination of hardware, firmware, and/or software implementations.

As illustrated in FIG. 6, entropy decoding unit 602 receives an entropyencoded bitstream. Entropy decoding unit 602 may be configured to decodesyntax elements and quantized coefficients from the bitstream accordingto a process reciprocal to an entropy encoding process. Entropy decodingunit 602 may be configured to perform entropy decoding according any ofthe entropy coding techniques described above. Entropy decoding unit 602may determine values for syntax elements in an encoded bitstream in amanner consistent with a video coding standard. As illustrated in FIG.6, entropy decoding unit 602 may determine a quantization parameter,quantized coefficient values, transform data, and prediction data from abitstream. In the example, illustrated in FIG. 6, inverse quantizationunit 604 and inverse transform coefficient processing unit 606 receive aquantization parameter, quantized coefficient values, transform data,and prediction data from entropy decoding unit 602 and outputreconstructed residual data.

Referring again to FIG. 6, reconstructed residual data may be providedto summer 612. Summer 612 may add reconstructed residual data to apredictive video block and generate reconstructed video data. Apredictive video block may be determined according to a predictive videotechnique (i.e., intra prediction and inter frame prediction). Intraprediction processing unit 608 may be configured to receive intraprediction syntax elements and retrieve a predictive video block fromreference buffer 616. Reference buffer 616 may include a memory deviceconfigured to store one or more frames of video data. Intra predictionsyntax elements may identify an intra prediction mode, such as the intraprediction modes described above. Inter prediction processing unit 610may receive inter prediction syntax elements and generate motion vectorsto identify a prediction block in one or more reference frames stored inreference buffer 616. Inter prediction processing unit 610 may producemotion compensated blocks, possibly performing interpolation based oninterpolation filters. Identifiers for interpolation filters to be usedfor motion estimation with sub-pixel precision may be included in thesyntax elements. Inter prediction processing unit 610 may useinterpolation filters to calculate interpolated values for sub-integerpixels of a reference block. Post filter unit 614 may be configured toperform filtering on reconstructed video data. For example, post filterunit 614 may be configured to perform deblocking and/or Sample AdaptiveOffset (SAO) filtering, e.g., based on parameters specified in abitstream. Further, it should be noted that in some examples, postfilter unit 614 may be configured to perform proprietary discretionaryfiltering (e.g., visual enhancements, such as, mosquito noisereduction). As illustrated in FIG. 6, a reconstructed video block may beoutput by video decoder 600. In this manner, video decoder 600represents an example of a device configured to parse a syntax elementin a sequence parameter set syntax structure specifying a maximum numberof temporal sublayers that may be present in each coded video sequencereferring to the sequence parameter set, parse a syntax elementspecifying a chroma sampling, and parse a syntax element specifying aluma coding tree block size, wherein the syntax element specifying achroma sampling and the syntax element specifying a luma coding treeblock size immediately follow the syntax element specifying a maximumnumber of temporal sublayers.

In one or more examples, the functions described may be implemented inhardware, software, firmware, or any combination thereof. If implementedin software, the functions may be stored on or transmitted over as oneor more instructions or code on a computer-readable medium and executedby a hardware-based processing unit. Computer-readable media may includecomputer-readable storage media, which corresponds to a tangible mediumsuch as data storage media, or communication media including any mediumthat facilitates transfer of a computer program from one place toanother, e.g., according to a communication protocol. In this manner,computer-readable media generally may correspond to (1) tangiblecomputer-readable storage media which is non-transitory or (2) acommunication medium such as a signal or carrier wave. Data storagemedia may be any available media that can be accessed by one or morecomputers or one or more processors to retrieve instructions, codeand/or data structures for implementation of the techniques described inthis disclosure. A computer program product may include acomputer-readable medium.

By way of example, and not limitation, such computer-readable storagemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage, or other magnetic storage devices, flashmemory, or any other medium that can be used to store desired programcode in the form of instructions or data structures and that can beaccessed by a computer. Also, any connection is properly termed acomputer-readable medium. For example, if instructions are transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of medium. It should be understood, however, thatcomputer-readable storage media and data storage media do not includeconnections, carrier waves, signals, or other transitory media, but areinstead directed to non-transitory, tangible storage media. Disk anddisc, as used herein, includes compact disc (CD), laser disc, opticaldisc, digital versatile disc (DVD), floppy disk and Blu-ray disc wheredisks usually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above should also be includedwithin the scope of computer-readable media.

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor,” as used herein may referto any of the foregoing structure or any other structure suitable forimplementation of the techniques described herein. In addition, in someaspects, the functionality described herein may be provided withindedicated hardware and/or software modules configured for encoding anddecoding, or incorporated in a combined codec. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide varietyof devices or apparatuses, including a wireless handset, an integratedcircuit (IC) or a set of ICs (e.g., a chip set). Various components,modules, or units are described in this disclosure to emphasizefunctional aspects of devices configured to perform the disclosedtechniques, but do not necessarily require realization by differenthardware units. Rather, as described above, various units may becombined in a codec hardware unit or provided by a collection ofinteroperative hardware units, including one or more processors asdescribed above, in conjunction with suitable software and/or firmware.

Moreover, each functional block or various features of the base stationdevice and the terminal device used in each of the aforementionedembodiments may be implemented or executed by a circuitry, which istypically an integrated circuit or a plurality of integrated circuits.The circuitry designed to execute the functions described in the presentspecification may comprise a general-purpose processor, a digital signalprocessor (DSP), an application specific or general applicationintegrated circuit (ASIC), a field programmable gate array (FPGA), orother programmable logic devices, discrete gates or transistor logic, ora discrete hardware component, or a combination thereof. Thegeneral-purpose processor may be a microprocessor, or alternatively, theprocessor may be a conventional processor, a controller, amicrocontroller or a state machine. The general-purpose processor oreach circuit described above may be configured by a digital circuit ormay be configured by an analogue circuit. Further, when a technology ofmaking into an integrated circuit superseding integrated circuits at thepresent time appears due to advancement of a semiconductor technology,the integrated circuit by this technology is also able to be used.

Various examples have been described. These and other examples arewithin the scope of the following claims.

What is claimed is:
 1. A method of decoding video data, the methodcomprising: receiving a sequence parameter set including syntax elementscorresponding to a coded video sequence; parsing a first byte of thesequence parameter set including a first syntax element and a secondsyntax element, wherein the first syntax element provides an identifierfor the sequence parameter set, and the second syntax element specifiesa video parameter set identifier referred to by the sequence parameterset; and parsing a second byte of the sequence parameter set including athird syntax element, a fourth syntax element, a fifth syntax elementand a sixth syntax element, wherein the third syntax element consists ofa first bit, a second bit, and a third bit of the second byte andspecifies a maximum number of temporal sublayers that may be present inthe coded video sequence referring to the sequence parameter set, thefourth syntax element consists of a fourth bit and a fifth bit of thesecond byte and specifies a chroma sampling relative to a luma sampling,the fifth syntax element consists of a sixth bit and a seventh bit ofthe second byte and specifies a luma coding tree block size of eachcoding tree unit, and the sixth syntax element consists of an eighth bitof the second byte and specifies whether level information is present inthe sequence parameter set.
 2. A device comprising one or moreprocessors configured to: receive a sequence parameter set includingsyntax elements corresponding to a coded video sequence; parse a firstbyte of the sequence parameter set including a first syntax element anda second syntax element, wherein the first syntax element provides anidentifier for the sequence parameter set, and the second syntax elementspecifies a video parameter set identifier referred to by the sequenceparameter set; and parse a second byte of the sequence parameter setincluding a third syntax element, a fourth syntax element, a fifthsyntax element and a sixth syntax element, wherein the third syntaxelement consists of a first bit, a second bit, and a third bit of thesecond byte and specifies a maximum number of temporal sublayers thatmay be present in the coded video sequence referring to the sequenceparameter set, the fourth syntax element consists of a fourth bit and afifth bit of the second byte and specifies a chroma sampling relative toa luma sampling, the fifth syntax element consists of a sixth bit and aseventh bit of the second byte and specifies a luma coding tree blocksize of each coding tree unit, and the sixth syntax element consists ofan eighth bit of the second byte and specifies whether level informationis present in the sequence parameter set.
 3. A method of signalingparameters for video data, the method comprising: signaling, in a firstbyte of a sequence parameter set, a first syntax element provides anidentifier for the sequence parameter set; signaling, in the first byteof the sequence parameter set, a second syntax element specifies a videoparameter set identifier referred to by the sequence parameter set;signaling, in a first bit, a second bit, and a third bit of a secondbyte of the sequence parameter set, a third syntax element specifying amaximum number of temporal sublayers that may be present in a codedvideo sequence referring to the sequence parameter set; signaling, in afourth bit and a fifth bit of the second byte, a fourth syntax elementspecifying a chroma sampling to a luma sampling; signaling, in a sixthbit and a seventh bit of the second byte, a fifth syntax elementspecifying a luma coding tree block size of each coding tree unit; andsignaling, in an eighth bit of the second byte of the sequence parameterset, a sixth syntax element specifying whether level information ispresent in the sequence parameter set.